Merge pull request 'feat(ext): verify cookies in-browser before uploading (1.0.7)' (#57 ) from dev into main

feat(ext): verify cookies in-browser before uploading (1.0.7)
Pre-upload verify request: after capturing the live browser cookies, hit a known authenticated endpoint with credentials:'include' from the extension's background context. If the platform reports we're not logged in, abort the upload so we don't overwrite FC-side credentials with stale data. - platforms.js: add `verify` config per cookie-auth platform - hentaifoundry: HEAD /?enterAgree=1 (mirrors gallery-dl's HF _init_site_filters; same 401 path the operator hit 2026-06-03) - patreon: GET /api/current_user (clean 401 when logged out) - subscribestar, deviantart: no stable auth endpoint, skip verify - cookies.js: verifyCookiesForPlatform() returns {ok, status, reason}. ok=true/false/null tri-state — null = verify not configured, caller treats as "proceed". - background.js EXPORT_COOKIES + EXPORT_ALL_COOKIES: verify gates the upload; failures bubble up with the platform's name + reason. - popup.js: success message now appends "(verified ✓)" when applicable. - manifest + package.json: 1.0.6 → 1.0.7.
2026-06-03 14:17:42 -04:00 · 2026-06-03 14:04:45 -04:00 · 2026-06-03 13:18:44 -04:00 · 2026-06-03 13:09:35 -04:00 · 2026-06-03 13:00:08 -04:00 · 2026-06-02 19:35:04 -04:00
289 changed files with 13122 additions and 5244 deletions
@@ -2,7 +2,17 @@ name: Build images

 on:
  push:
-    branches: [dev, main]
+    # `:dev` builds dropped 2026-05-26 — operator tests from `:latest` after
+    # merge-to-main, not from the dev branch image. Saves one full docker
+    # build per dev push.
+    branches: [main]
+    # Tag-push triggers an immutable per-version image build (e.g.
+    # `:v26.05.26.5`) — gives a real rollback story alongside the floating
+    # `:main` / `:latest`. Layer reuse keeps the registry-storage cost
+    # negligible per tag. Doesn't overlap with the push-to-main build (that
+    # one publishes `:main` + `:latest`; the tag-push build publishes only
+    # `:<tag>`).
+    tags: ['v*']

 # Requires repo secret RELEASE_TOKEN — a Forgejo PAT with scopes:
 #   - write:package, read:package  (for docker push to git.fabledsword.com)
@@ -158,25 +168,56 @@ jobs:
    steps:
      - uses: actions/checkout@v4

-      - name: Download signed XPI from Forgejo release asset (main only)
-        if: github.ref == 'refs/heads/main'
+      - name: Download signed XPI from Forgejo release asset (main + tags)
+        # Fires on main-push AND on tag-push. Tag-push builds re-package the
+        # same source code as the preceding main-push build but with an
+        # immutable version tag — they need the XPI too, otherwise the
+        # versioned image ships without the signed extension.
+        #
+        # Tag-push vs main-push race (operator-flagged 2026-05-27 after
+        # v26.05.27.0 hit it): a release cut fires BOTH workflows almost
+        # simultaneously. Main-push runs sign-extension (1-5min AMO round
+        # trip) before publishing the ext-<version> release; tag-push
+        # skips sign-extension (gated to main) and races straight to
+        # this download step. Tag-push lost every time. Fix: poll the
+        # ext-<version> release endpoint with a sleep+retry loop (30s
+        # for up to 10min total) before giving up. Main-push's signing
+        # eventually wins and tag-push picks the release up on a later
+        # iteration.
+        if: github.ref == 'refs/heads/main' || startsWith(github.ref, 'refs/tags/')
        env:
          TOKEN: ${{ secrets.RELEASE_TOKEN }}
        run: |
          set -eux
          VERSION=$(grep -E '"version"' extension/package.json | head -1 | sed -E 's/.*"version"[[:space:]]*:[[:space:]]*"([^"]+)".*/\1/')
-          # Look up the ext-<version> release; extract the .xpi asset's
-          # browser_download_url (Forgejo's /releases/assets/<id> endpoint
-          # returns ASSET METADATA, not the binary blob — operator-flagged
-          # 2026-05-26: my prior code curl'd the metadata endpoint without
-          # -f and wrote the resulting 404-page-not-found text into
-          # fabledcurator-*.xpi, which Firefox then rejected as "corrupt").
-          # browser_download_url is the canonical binary endpoint and is
-          # also publicly accessible (no token needed) but we pass the
-          # token anyway for symmetry with private-repo support.
-          curl -sf -H "Authorization: token $TOKEN" \
-            "https://git.fabledsword.com/api/v1/repos/bvandeusen/FabledCurator/releases/tags/ext-$VERSION" \
-            -o release.json
+          # Poll for the ext-<version> release. main-push's sign-extension
+          # step (AMO round-trip, 1-5min) needs to finish + upload before
+          # tag-push can fetch. 30s * 20 = up to 10min wait, then hard-fail.
+          for attempt in $(seq 1 20); do
+            STATUS=$(curl -s -o release.json -w "%{http_code}" \
+              -H "Authorization: token $TOKEN" \
+              "https://git.fabledsword.com/api/v1/repos/bvandeusen/FabledCurator/releases/tags/ext-$VERSION" || echo 000)
+            if [ "$STATUS" = "200" ]; then
+              echo "Found ext-$VERSION release on attempt $attempt"
+              break
+            fi
+            if [ "$attempt" = "20" ]; then
+              echo "ERROR: ext-$VERSION release not available after 10min of polling"
+              echo "Last HTTP status: $STATUS"
+              exit 1
+            fi
+            echo "Attempt $attempt: ext-$VERSION not yet published (HTTP $STATUS); sleeping 30s"
+            sleep 30
+          done
+          # Extract the .xpi asset's browser_download_url (Forgejo's
+          # /releases/assets/<id> endpoint returns ASSET METADATA, not
+          # the binary blob — operator-flagged 2026-05-26: my prior
+          # code curl'd the metadata endpoint without -f and wrote the
+          # resulting 404-page-not-found text into fabledcurator-*.xpi,
+          # which Firefox then rejected as "corrupt").
+          # browser_download_url is the canonical binary endpoint and
+          # is also publicly accessible (no token needed) but we pass
+          # the token anyway for symmetry with private-repo support.
          DOWNLOAD_URL=$(python3 -c "import json; r=json.load(open('release.json')); xpis=[a for a in r.get('assets', []) if a.get('name','').endswith('.xpi')]; print(xpis[0]['browser_download_url'])")
          test -n "$DOWNLOAD_URL"
          echo "Downloading XPI from: $DOWNLOAD_URL"
@@ -200,8 +241,33 @@ jobs:
      - name: Determine tag
        id: tag
        run: |
-          if [ "${GITHUB_REF##*/}" = "main" ]; then
-            echo "tags=git.fabledsword.com/bvandeusen/fabledcurator:main,git.fabledsword.com/bvandeusen/fabledcurator:latest" >> "$GITHUB_OUTPUT"
+          # Three trigger shapes:
+          #   refs/tags/v…   → tag-push: opt-in milestone label (vYY.MM.DD,
+          #                    no `.N` per family release-posture rule).
+          #                    Publish ONLY the immutable version tag;
+          #                    don't touch :latest (the main-push build
+          #                    for the merge commit already did that).
+          #   refs/heads/main → push to main: publish :main + :latest
+          #                    (floating) AND :c-<short_sha> (immutable
+          #                    per-commit rollback substrate, per family
+          #                    release-posture rule "Tags are milestones,
+          #                    not gates — commit-SHA images are the
+          #                    rollback unit"). Rollback to any commit
+          #                    becomes `docker pull …:c-<sha>` without a
+          #                    release ceremony.
+          #   anything else  → safety net; shouldn't fire given the `on:`
+          #                    config above. Tag :dev to surface the
+          #                    unexpected run in the registry.
+          # POSIX-safe substring (the runner shell is dash/BusyBox sh, not
+          # bash — `${var:0:7}` errors with "Bad substitution"; cut works
+          # everywhere). Operator-flagged 2026-06-01 after first :c-<sha>
+          # main-push build failed at this step.
+          SHORT_SHA=$(printf '%s' "$GITHUB_SHA" | cut -c1-7)
+          if [ "${GITHUB_REF#refs/tags/}" != "${GITHUB_REF}" ]; then
+            TAG_NAME="${GITHUB_REF#refs/tags/}"
+            echo "tags=git.fabledsword.com/bvandeusen/fabledcurator:${TAG_NAME}" >> "$GITHUB_OUTPUT"
+          elif [ "${GITHUB_REF##*/}" = "main" ]; then
+            echo "tags=git.fabledsword.com/bvandeusen/fabledcurator:main,git.fabledsword.com/bvandeusen/fabledcurator:latest,git.fabledsword.com/bvandeusen/fabledcurator:c-${SHORT_SHA}" >> "$GITHUB_OUTPUT"
          else
            echo "tags=git.fabledsword.com/bvandeusen/fabledcurator:dev" >> "$GITHUB_OUTPUT"
          fi
@@ -231,8 +297,20 @@ jobs:
      - name: Determine tag
        id: tag
        run: |
-          if [ "${GITHUB_REF##*/}" = "main" ]; then
-            echo "tags=git.fabledsword.com/bvandeusen/fabledcurator-ml:main,git.fabledsword.com/bvandeusen/fabledcurator-ml:latest" >> "$GITHUB_OUTPUT"
+          # Mirrors build-web's three-shape logic (tag-push / main-push /
+          # safety-net dev) including the per-commit :c-<short_sha> tag
+          # on main-push per the family release-posture rule. The -ml
+          # image follows the same release cadence as the web image.
+          # POSIX-safe substring (the runner shell is dash/BusyBox sh, not
+          # bash — `${var:0:7}` errors with "Bad substitution"; cut works
+          # everywhere). Operator-flagged 2026-06-01 after first :c-<sha>
+          # main-push build failed at this step.
+          SHORT_SHA=$(printf '%s' "$GITHUB_SHA" | cut -c1-7)
+          if [ "${GITHUB_REF#refs/tags/}" != "${GITHUB_REF}" ]; then
+            TAG_NAME="${GITHUB_REF#refs/tags/}"
+            echo "tags=git.fabledsword.com/bvandeusen/fabledcurator-ml:${TAG_NAME}" >> "$GITHUB_OUTPUT"
+          elif [ "${GITHUB_REF##*/}" = "main" ]; then
+            echo "tags=git.fabledsword.com/bvandeusen/fabledcurator-ml:main,git.fabledsword.com/bvandeusen/fabledcurator-ml:latest,git.fabledsword.com/bvandeusen/fabledcurator-ml:c-${SHORT_SHA}" >> "$GITHUB_OUTPUT"
          else
            echo "tags=git.fabledsword.com/bvandeusen/fabledcurator-ml:dev" >> "$GITHUB_OUTPUT"
          fi
@@ -1,17 +1,34 @@
 name: CI

 # CI lanes per FabledRulebook/forgejo.md "CI philosophy":
-#   - backend-lint-and-test: ruff + `pytest -m "not integration"`, no service containers.
+#   - lint: ruff only, no dep install — fast-fail for the common lint bounce.
+#   - backend-lint-and-test: `pytest -m "not integration"`, no service containers.
 #   - frontend-build: vitest unit + vite build.
 #   - integration: pgvector + redis service containers; alembic + `pytest -m integration`.

 on:
  push:
    branches: [dev, main]
-  pull_request:
-    branches: [main]
+  # pull_request trigger intentionally absent — with branches: [dev, main]
+  # above, every PR commit already fires CI via the push event on dev. Adding
+  # pull_request would duplicate runs on dev→main PRs. FC has no fork PRs
+  # (single-operator Forgejo repo) so push coverage is complete.

 jobs:
+  # Fast-fail lint lane. ruff is pre-installed in the ci-python image, so
+  # this runs with NO dependency install and surfaces the most common bounce
+  # class (lint: I001 / UP037 / ASYNC109 / W293 …) in seconds — instead of
+  # after the backend job's ~30-60s wheel install. ruff is static analysis,
+  # so no DB/secret env is needed.
+  lint:
+    runs-on: python-ci
+    container:
+      image: git.fabledsword.com/bvandeusen/ci-python:3.14
+    steps:
+      - uses: actions/checkout@v4
+      - name: Ruff lint
+        run: ruff check backend/ tests/ alembic/
+
  backend-lint-and-test:
    runs-on: python-ci
    container:
@@ -24,22 +41,17 @@ jobs:
    steps:
      - uses: actions/checkout@v4

-      - name: Cache pip wheels
-        # continue-on-error: act_runner's cache backend has been broken on
-        # this homelab setup since 2026-05-15 — bolt.db + cache/ dir exist
-        # but the action's JS bundle now fails to load at all
-        # ("Cannot find module .../dist/restore/index.js"), hard-failing
-        # the whole job. The install step that follows handles cold caches
-        # natively (uv pip / pip install both work without it), so net
-        # cost of disabling the cache here is ~30s of wheel downloads per
-        # job. Re-enable once the runner-side cache backend is fixed.
-        continue-on-error: true
-        uses: actions/cache@v4
-        with:
-          path: ~/.cache/pip
-          key: pip-${{ runner.os }}-py314-${{ hashFiles('requirements.txt') }}
-          restore-keys: |
-            pip-${{ runner.os }}-py314-
+      # Cache step removed 2026-05-26: act_runner's cache backend has been
+      # broken on this homelab runner since 2026-05-15 (first as request-
+      # timeout warnings, then as hard "Cannot find module .../dist/restore/
+      # index.js" failures that tank the whole job). The cache step targeted
+      # ~/.cache/pip but the install below uses `uv pip install` primarily,
+      # whose own cache lives at ~/.cache/uv — so the cache step's real
+      # benefit was marginal even when working. Cost of removal: ~30s of
+      # wheel downloads per job. Future re-enable: mount ~/.cache/uv as a
+      # docker volume at the runner level (skips actions/cache entirely),
+      # or fix the runner-side cache backend (clear /var/run/act/actions/*,
+      # pin act_runner version, etc.).

      - name: Install Python deps
        # ruff is pre-installed in the ci-python image (see CI-Runner/CI-python/
@@ -54,9 +66,8 @@ jobs:
            pip install -r requirements.txt pytest pytest-asyncio
          fi

-      - name: Ruff lint
-        run: ruff check backend/ tests/ alembic/
-
+      # Ruff moved to the dedicated fast `lint` job above (fails in seconds,
+      # no dep install). This job is now unit tests only.
      - name: Pytest (unit only — integration runs in the integration job)
        run: pytest tests/ -v -m "not integration"

@@ -133,22 +144,6 @@ jobs:
          --health-retries 10
    steps:
      - uses: actions/checkout@v4
-      - name: Cache pip wheels
-        # continue-on-error: act_runner's cache backend has been broken on
-        # this homelab setup since 2026-05-15 — bolt.db + cache/ dir exist
-        # but the action's JS bundle now fails to load at all
-        # ("Cannot find module .../dist/restore/index.js"), hard-failing
-        # the whole job. The install step that follows handles cold caches
-        # natively (uv pip / pip install both work without it), so net
-        # cost of disabling the cache here is ~30s of wheel downloads per
-        # job. Re-enable once the runner-side cache backend is fixed.
-        continue-on-error: true
-        uses: actions/cache@v4
-        with:
-          path: ~/.cache/pip
-          key: pip-${{ runner.os }}-py314-${{ hashFiles('requirements.txt') }}
-          restore-keys: |
-            pip-${{ runner.os }}-py314-
      - name: API integration shard (resolve service IPs, migrate, test)
        run: |
          set -eux
@@ -207,22 +202,6 @@ jobs:
          --health-retries 10
    steps:
      - uses: actions/checkout@v4
-      - name: Cache pip wheels
-        # continue-on-error: act_runner's cache backend has been broken on
-        # this homelab setup since 2026-05-15 — bolt.db + cache/ dir exist
-        # but the action's JS bundle now fails to load at all
-        # ("Cannot find module .../dist/restore/index.js"), hard-failing
-        # the whole job. The install step that follows handles cold caches
-        # natively (uv pip / pip install both work without it), so net
-        # cost of disabling the cache here is ~30s of wheel downloads per
-        # job. Re-enable once the runner-side cache backend is fixed.
-        continue-on-error: true
-        uses: actions/cache@v4
-        with:
-          path: ~/.cache/pip
-          key: pip-${{ runner.os }}-py314-${{ hashFiles('requirements.txt') }}
-          restore-keys: |
-            pip-${{ runner.os }}-py314-
      - name: Importer integration shard (resolve service IPs, migrate, test)
        run: |
          set -eux
@@ -281,22 +260,6 @@ jobs:
          --health-retries 10
    steps:
      - uses: actions/checkout@v4
-      - name: Cache pip wheels
-        # continue-on-error: act_runner's cache backend has been broken on
-        # this homelab setup since 2026-05-15 — bolt.db + cache/ dir exist
-        # but the action's JS bundle now fails to load at all
-        # ("Cannot find module .../dist/restore/index.js"), hard-failing
-        # the whole job. The install step that follows handles cold caches
-        # natively (uv pip / pip install both work without it), so net
-        # cost of disabling the cache here is ~30s of wheel downloads per
-        # job. Re-enable once the runner-side cache backend is fixed.
-        continue-on-error: true
-        uses: actions/cache@v4
-        with:
-          path: ~/.cache/pip
-          key: pip-${{ runner.os }}-py314-${{ hashFiles('requirements.txt') }}
-          restore-keys: |
-            pip-${{ runner.os }}-py314-
      - name: Core integration shard (everything not api / importer / migration / phash / sidecar / scan / archive / backfill)
        run: |
          set -eux
@@ -83,55 +83,80 @@ def upgrade() -> None:
        if not other_ids:
            continue

-        # STEP 2: PRE-merge colliding Posts BEFORE the bulk reparent.
-        # Find pairs (keep, drop) where:
-        #   keep  = a Post under the canonical source
-        #   drop  = a Post under one of the non-canonical sources whose
-        #           external_post_id equals keep.external_post_id
-        # If we let the bulk UPDATE try to repoint drop onto canonical,
-        # uq_post_source_external_id fires row-by-row and aborts the
-        # whole migration.
-        colliding = conn.execute(
+        # STEP 2: PRE-merge ALL Posts with duplicate external_post_id
+        # across the entire (canonical + others) group, BEFORE the bulk
+        # reparent. Two cases must both be handled:
+        #   (A) canonical has Post X with epid=N; an "other" source has
+        #       Post Y with epid=N → after bulk UPDATE, (canonical, N)
+        #       collides with itself.
+        #   (B) two different "other" sources each have a Post with
+        #       epid=N; canonical has none → after bulk UPDATE, both
+        #       are repointed to (canonical, N) and the second collides.
+        # The earlier version of this migration only handled (A); the
+        # operator's deploy 2026-05-26 tripped (B) at line 139.
+        # Fix: group ALL Posts in the (artist, platform) by epid; for
+        # any group with count>1, pick the keep (prefer one already
+        # under canonical; else lowest id) and merge the rest into it.
+        all_posts = conn.execute(
            text("""
-                SELECT keep.id AS keep_id, drop_.id AS drop_id
-                FROM post AS keep
-                JOIN post AS drop_
-                  ON drop_.external_post_id = keep.external_post_id
-                 AND drop_.id != keep.id
-                WHERE keep.source_id = :canonical
-                  AND drop_.source_id = ANY(:others)
+                SELECT external_post_id, id, source_id
+                FROM post
+                WHERE source_id = :canonical OR source_id = ANY(:others)
+                ORDER BY external_post_id, id
            """),
            {"canonical": canonical_id, "others": other_ids},
        ).fetchall()
-        for keep_id, drop_id in colliding:
-            conn.execute(
-                text("""
-                    UPDATE image_provenance SET post_id = :keep
-                    WHERE post_id = :drop_
-                """),
-                {"keep": keep_id, "drop_": drop_id},
-            )
-            conn.execute(
-                text("""
-                    UPDATE image_record SET primary_post_id = :keep
-                    WHERE primary_post_id = :drop_
-                """),
-                {"keep": keep_id, "drop_": drop_id},
-            )
-            # Repointed provenance may now collide on
-            # uq_image_provenance_image_post (alembic 0021). Dedupe:
-            # keep min(id) per (image_record_id, post_id).
-            conn.execute(text("""
-                DELETE FROM image_provenance ip1
-                USING image_provenance ip2
-                WHERE ip1.image_record_id = ip2.image_record_id
-                  AND ip1.post_id = ip2.post_id
-                  AND ip1.id > ip2.id
-            """))
-            conn.execute(
-                text("DELETE FROM post WHERE id = :drop_"),
-                {"drop_": drop_id},
-            )
+        by_epid: dict = {}
+        for epid, post_id, src_id in all_posts:
+            by_epid.setdefault(epid, []).append((post_id, src_id))
+        for _epid, posts in by_epid.items():
+            if len(posts) <= 1:
+                continue
+            # Prefer a Post already under canonical as the keep.
+            canonical_posts = [p for p in posts if p[1] == canonical_id]
+            if canonical_posts:
+                keep_id = canonical_posts[0][0]
+            else:
+                keep_id = posts[0][0]  # already sorted by id ASC
+            drop_ids = [p[0] for p in posts if p[0] != keep_id]
+            for drop_id in drop_ids:
+                # Pre-delete image_provenance rows under drop_ whose
+                # image_record_id ALREADY has a provenance under keep —
+                # the UPDATE below would otherwise repoint them and
+                # trip uq_image_provenance_image_post (alembic 0021)
+                # row-by-row before any after-the-fact dedupe could
+                # run. Operator's v26.05.26.3 deploy 2026-05-26 tripped
+                # this at line 123.
+                conn.execute(
+                    text("""
+                        DELETE FROM image_provenance
+                        WHERE post_id = :drop_
+                          AND image_record_id IN (
+                              SELECT image_record_id FROM image_provenance
+                              WHERE post_id = :keep
+                          )
+                    """),
+                    {"keep": keep_id, "drop_": drop_id},
+                )
+                # Now safe to repoint the survivors.
+                conn.execute(
+                    text("""
+                        UPDATE image_provenance SET post_id = :keep
+                        WHERE post_id = :drop_
+                    """),
+                    {"keep": keep_id, "drop_": drop_id},
+                )
+                conn.execute(
+                    text("""
+                        UPDATE image_record SET primary_post_id = :keep
+                        WHERE primary_post_id = :drop_
+                    """),
+                    {"keep": keep_id, "drop_": drop_id},
+                )
+                conn.execute(
+                    text("DELETE FROM post WHERE id = :drop_"),
+                    {"drop_": drop_id},
+                )

        # STEP 3: Bulk reparent the remaining Posts off the other
        # Sources. After step 2, no collisions on
@@ -0,0 +1,99 @@
+"""drop meta + rating tag kinds — operator-retired 2026-05-26
+
+Revision ID: 0023
+Revises: 0022
+Create Date: 2026-05-26
+
+Operator decided meta + rating aren't valid tag kinds for FC. Per-row
+behavior: DELETE existing rows (operator chose "clean break" over
+"convert to general"). All cascading FKs (image_tag, tag_alias,
+tag_allowlist, tag_reference_embedding, tag_suggestion_rejection,
+series_page) use ondelete="CASCADE" so a single DELETE on tag cleans
+the related rows in one go.
+
+After the data cleanup, recreate the tag_kind ENUM without 'meta' /
+'rating' (Postgres has no `ALTER TYPE ... DROP VALUE`; standard
+rename-create-cast-drop dance). The server default 'general' is
+dropped before the type swap and restored after.
+"""
+from typing import Sequence, Union
+
+from alembic import op
+
+revision: str = "0023"
+down_revision: Union[str, None] = "0022"
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    # 1. Delete tags of the retired kinds. CASCADE handles related tables.
+    op.execute("DELETE FROM tag WHERE kind IN ('meta', 'rating')")
+
+    # 2. Drop the CHECK constraint that references the enum's literal
+    #    values. Postgres can't resolve `kind = 'character'` across the
+    #    type swap below — the literal would bind to the new tag_kind
+    #    but the column is on tag_kind_old, producing
+    #    "operator does not exist: tag_kind = tag_kind_old".
+    #    (Operator-hit during the v26.05.26.5 deploy attempt; ck was
+    #    originally added by alembic 0002.) Recreated post-swap.
+    op.drop_constraint(
+        "ck_tag_fandom_requires_character", "tag", type_="check"
+    )
+
+    # 3. Drop the server default — ALTER COLUMN TYPE can't carry it
+    #    across the type swap below.
+    op.execute("ALTER TABLE tag ALTER COLUMN kind DROP DEFAULT")
+
+    # 4. Recreate the tag_kind enum without meta/rating.
+    op.execute("ALTER TYPE tag_kind RENAME TO tag_kind_old")
+    op.execute(
+        "CREATE TYPE tag_kind AS ENUM ("
+        "'artist', 'character', 'fandom', 'general', "
+        "'series', 'archive', 'post'"
+        ")"
+    )
+    op.execute(
+        "ALTER TABLE tag "
+        "ALTER COLUMN kind TYPE tag_kind "
+        "USING kind::text::tag_kind"
+    )
+    op.execute("DROP TYPE tag_kind_old")
+
+    # 5. Restore the server default.
+    op.execute("ALTER TABLE tag ALTER COLUMN kind SET DEFAULT 'general'")
+
+    # 6. Restore the CHECK constraint (now bound to the new tag_kind).
+    op.create_check_constraint(
+        "ck_tag_fandom_requires_character",
+        "tag",
+        "(fandom_id IS NULL) OR (kind = 'character')",
+    )
+
+
+def downgrade() -> None:
+    # Add the values back to the enum so old code can boot. The deleted
+    # tag rows are gone permanently — no safe restore.
+    op.drop_constraint(
+        "ck_tag_fandom_requires_character", "tag", type_="check"
+    )
+    op.execute("ALTER TABLE tag ALTER COLUMN kind DROP DEFAULT")
+    op.execute("ALTER TYPE tag_kind RENAME TO tag_kind_old")
+    op.execute(
+        "CREATE TYPE tag_kind AS ENUM ("
+        "'artist', 'character', 'fandom', 'general', "
+        "'series', 'archive', 'post', 'meta', 'rating'"
+        ")"
+    )
+    op.execute(
+        "ALTER TABLE tag "
+        "ALTER COLUMN kind TYPE tag_kind "
+        "USING kind::text::tag_kind"
+    )
+    op.execute("DROP TYPE tag_kind_old")
+    op.execute("ALTER TABLE tag ALTER COLUMN kind SET DEFAULT 'general'")
+    op.create_check_constraint(
+        "ck_tag_fandom_requires_character",
+        "tag",
+        "(fandom_id IS NULL) OR (kind = 'character')",
+    )
@@ -0,0 +1,80 @@
+"""backfill post.post_title from description first-line — 2026-05-27
+
+Revision ID: 0024
+Revises: 0023
+Create Date: 2026-05-27
+
+SubscribeStar gallery-dl always writes `title: ""` and embeds the leading
+sentence inside `content` HTML. FC's sidecar parser was leaving
+post_title NULL for every SubscribeStar post since FC-3 shipped. The
+parser fix (sidecar._first_line_text fallback) now synthesizes a title
+at parse time; this migration applies the same logic retroactively to
+existing rows.
+
+Operator-flagged 2026-05-27 after inspecting
+/mnt/Data/Patreon/Cheunart/subscribestar/ sidecars.
+
+Idempotent: only touches rows where post_title IS NULL or empty AND
+description IS NOT NULL. Re-running the migration is a no-op.
+"""
+from __future__ import annotations
+
+import re
+from typing import Sequence, Union
+
+from alembic import op
+from sqlalchemy import text
+
+revision: str = "0024"
+down_revision: Union[str, None] = "0023"
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+_TAG_RE = re.compile(r"<[^>]+>")
+_WS_RE = re.compile(r"\s+")
+
+
+def _first_line_text(body: str, limit: int = 120) -> str | None:
+    """Mirror of sidecar._first_line_text. Kept inline so the migration
+    doesn't carry a runtime import dependency from app code that may
+    have moved by the time the migration is replayed years from now."""
+    if not body:
+        return None
+    text_ = _TAG_RE.sub(" ", body)
+    text_ = text_.replace("\xa0", " ")
+    for line in text_.splitlines():
+        line = _WS_RE.sub(" ", line).strip()
+        if line:
+            if len(line) > limit:
+                return line[: limit - 1].rstrip() + "…"
+            return line
+    return None
+
+
+def upgrade() -> None:
+    bind = op.get_bind()
+    rows = bind.execute(
+        text(
+            "SELECT id, description FROM post "
+            "WHERE (post_title IS NULL OR post_title = '') "
+            "AND description IS NOT NULL AND description <> ''"
+        )
+    ).fetchall()
+    updated = 0
+    for row in rows:
+        derived = _first_line_text(row.description)
+        if not derived:
+            continue
+        bind.execute(
+            text("UPDATE post SET post_title = :t WHERE id = :id"),
+            {"t": derived, "id": row.id},
+        )
+        updated += 1
+    print(f"0024: backfilled post_title on {updated} row(s)")
+
+
+def downgrade() -> None:
+    # No safe restore — we can't tell which post_titles were derived vs
+    # genuinely present. Leave the column alone on rollback.
+    pass
@@ -0,0 +1,288 @@
+"""sidecar-audit followup: correct external_post_id + post_url across all platforms
+
+Revision ID: 0025
+Revises: 0024
+Create Date: 2026-05-27
+
+Closes the operator-flagged 2026-05-27 sidecar audit findings. Three
+data-correctness bugs across non-Patreon platforms had been silently
+corrupting Posts since FC-3 shipped; the parser fix (sidecar.py, same
+commit) addresses new imports. This migration cleans up existing rows.
+
+Per-platform actions:
+
+  subscribestar — gallery-dl wrote the per-attachment id in `id` and
+    the actual post id in `post_id`. FC's parser picked `id`, so every
+    multi-image SubscribeStar post was fragmented into N Post rows.
+    1. For each SubscribeStar Post, read its sidecar (via the related
+       ImageRecord's on-disk path), pull `post_id`, overwrite
+       external_post_id and post_url.
+    2. Merge groups of Posts under one source that now share an
+       external_post_id (fragments of the same actual post). Same
+       ImageProvenance pre-delete + repoint dance as alembic 0022.
+
+  hentaifoundry — sidecars have NO `url` field; `src` is the image
+    URL. FC's parser stored post_url=NULL. Read each HF Post's sidecar
+    for `user` + `index`, derive the canonical /pictures/user/<u>/<i>
+    permalink. external_post_id (= `index`) was already correct.
+
+  discord — gallery-dl wrote the CDN attachment URL in `url`. FC's
+    parser stored that as post_url. Read each Discord Post's sidecar
+    for the server/channel/message triple, derive the proper
+    discord.com/channels/.../<message> permalink. external_post_id (=
+    `message_id`) was already correct.
+
+  pixiv — pure-SQL backfill: replace any `i.pximg.net`-style URL on
+    Post.post_url with the derived `/artworks/<id>` permalink. Pixiv
+    external_post_id (= `id`) was already correct; no sidecar IO
+    needed.
+
+Idempotent: re-running on already-corrected data is a no-op (skips
+rows whose derived value matches what's already stored).
+
+Posts whose related ImageRecord paths don't resolve on disk (orphaned
+filesystem state) are skipped with a count in the migration output —
+those will be picked up by a future deep-scan.
+"""
+from __future__ import annotations
+
+import json
+import re
+from pathlib import Path
+from typing import Sequence, Union
+
+from alembic import op
+from sqlalchemy import text
+
+revision: str = "0025"
+down_revision: Union[str, None] = "0024"
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+# Mirror of sidecar._NUMBERING_PREFIX. Kept inline so the migration is
+# self-contained (the operator's banked rule:
+# reference_postgres_enum_swap_drop_checks.md says migrations shouldn't
+# import from runtime app code).
+_NUMBERING_PREFIX = re.compile(r"^\d+_(.+)$")
+
+
+def _find_sidecar(media_path: Path) -> Path | None:
+    """gallery-dl writes the sidecar under the unprefixed stem
+    (`HOLLOW-ICHIGO.json`) while the media file gets a NN_ ordering
+    prefix (`01_HOLLOW-ICHIGO.png`). Try in order:
+      1. <stem>.json next to the media
+      2. <media>.json next to the media (full-name variant)
+      3. strip the NN_ prefix from the stem, then <stripped>.json
+    """
+    if not media_path:
+        return None
+    cand = media_path.with_suffix(".json")
+    if cand.is_file():
+        return cand
+    cand = media_path.parent / f"{media_path.name}.json"
+    if cand.is_file():
+        return cand
+    m = _NUMBERING_PREFIX.match(media_path.stem)
+    if m:
+        cand = media_path.parent / f"{m.group(1)}.json"
+        if cand.is_file():
+            return cand
+    return None
+
+
+def _str_id(v) -> str | None:
+    """str() a JSON scalar id; reject bool (JSON booleans are ints in
+    Python's eyes but they aren't valid sidecar ids)."""
+    if isinstance(v, bool):
+        return None
+    if isinstance(v, (str, int)) and str(v).strip():
+        return str(v).strip()
+    return None
+
+
+def _str_field(v) -> str | None:
+    if isinstance(v, str) and v.strip():
+        return v.strip()
+    return None
+
+
+def upgrade() -> None:
+    conn = op.get_bind()
+
+    # ── PART 1: Per-platform corrections requiring filesystem IO ─────
+    # SubscribeStar, HentaiFoundry, Discord all need fields from the
+    # sidecar to construct the right post_url. We walk each Post's
+    # related ImageRecord.path to find the sidecar, read it, derive,
+    # and update.
+    targets = conn.execute(text("""
+        SELECT p.id, p.external_post_id, p.post_url, s.platform
+        FROM post p
+        JOIN source s ON s.id = p.source_id
+        WHERE s.platform IN ('subscribestar', 'hentaifoundry', 'discord')
+    """)).fetchall()
+
+    stats: dict[str, dict[str, int]] = {
+        plat: {"read": 0, "updated": 0, "no_sidecar": 0}
+        for plat in ("subscribestar", "hentaifoundry", "discord")
+    }
+    for post_row in targets:
+        plat = post_row.platform
+        path = _first_attachment_path(conn, post_row.id)
+        if not path:
+            stats[plat]["no_sidecar"] += 1
+            continue
+        sidecar = _find_sidecar(Path(path))
+        if sidecar is None:
+            stats[plat]["no_sidecar"] += 1
+            continue
+        try:
+            data = json.loads(sidecar.read_text(encoding="utf-8"))
+        except (OSError, json.JSONDecodeError):
+            stats[plat]["no_sidecar"] += 1
+            continue
+        stats[plat]["read"] += 1
+
+        new_epid = post_row.external_post_id
+        new_url = None
+        if plat == "subscribestar":
+            pid = _str_id(data.get("post_id"))
+            if pid:
+                new_epid = pid
+                new_url = f"https://www.subscribestar.com/posts/{pid}"
+        elif plat == "hentaifoundry":
+            user = _str_field(data.get("user")) or _str_field(data.get("artist"))
+            idx = _str_id(data.get("index"))
+            if user and idx:
+                new_url = f"https://www.hentai-foundry.com/pictures/user/{user}/{idx}"
+        elif plat == "discord":
+            sid = _str_id(data.get("server_id"))
+            cid = _str_id(data.get("channel_id"))
+            mid = _str_id(data.get("message_id"))
+            if sid and cid and mid:
+                new_url = f"https://discord.com/channels/{sid}/{cid}/{mid}"
+
+        # Idempotent: skip if nothing changed.
+        if new_epid == post_row.external_post_id and new_url == post_row.post_url:
+            continue
+        conn.execute(
+            text("""
+                UPDATE post
+                SET external_post_id = :epid, post_url = :url
+                WHERE id = :id
+            """),
+            {"epid": new_epid, "url": new_url, "id": post_row.id},
+        )
+        stats[plat]["updated"] += 1
+
+    for plat, s in stats.items():
+        print(
+            f"0025: {plat} — read {s['read']} sidecars, "
+            f"updated {s['updated']} Posts, "
+            f"{s['no_sidecar']} Posts had no resolvable sidecar"
+        )
+
+    # ── PART 2: Merge SubscribeStar fragments now sharing epid ───────
+    # After Part 1, each group of Posts under one source with the SAME
+    # new external_post_id is a fragment-set of the same actual post.
+    # Merge to one canonical row. Pre-handle the same ImageProvenance
+    # collision pattern as alembic 0022 (uq_image_provenance_image_post).
+    fragment_groups = conn.execute(text("""
+        SELECT p.source_id, p.external_post_id,
+               ARRAY_AGG(p.id ORDER BY p.id ASC) AS post_ids
+        FROM post p
+        JOIN source s ON s.id = p.source_id
+        WHERE s.platform = 'subscribestar'
+          AND p.external_post_id IS NOT NULL
+        GROUP BY p.source_id, p.external_post_id
+        HAVING COUNT(*) > 1
+    """)).fetchall()
+
+    merged = 0
+    for grp in fragment_groups:
+        post_ids = list(grp.post_ids)
+        keep_id, *drop_ids = post_ids
+        for drop_id in drop_ids:
+            # Pre-DELETE colliding ImageProvenance under drop_ that
+            # already exist under keep (alembic 0022 banked the pattern).
+            conn.execute(
+                text("""
+                    DELETE FROM image_provenance
+                    WHERE post_id = :drop_
+                      AND image_record_id IN (
+                          SELECT image_record_id FROM image_provenance
+                          WHERE post_id = :keep
+                      )
+                """),
+                {"keep": keep_id, "drop_": drop_id},
+            )
+            conn.execute(
+                text("""
+                    UPDATE image_provenance SET post_id = :keep
+                    WHERE post_id = :drop_
+                """),
+                {"keep": keep_id, "drop_": drop_id},
+            )
+            conn.execute(
+                text("""
+                    UPDATE image_record SET primary_post_id = :keep
+                    WHERE primary_post_id = :drop_
+                """),
+                {"keep": keep_id, "drop_": drop_id},
+            )
+            conn.execute(
+                text("""
+                    UPDATE post_attachment SET post_id = :keep
+                    WHERE post_id = :drop_
+                """),
+                {"keep": keep_id, "drop_": drop_id},
+            )
+            conn.execute(
+                text("DELETE FROM post WHERE id = :drop_"),
+                {"drop_": drop_id},
+            )
+            merged += 1
+    print(f"0025: subscribestar — merged {merged} duplicate Post fragments")
+
+    # ── PART 3: Pixiv post_url backfill (pure SQL) ───────────────────
+    # Pixiv's external_post_id is already correct (gallery-dl's `id` is
+    # the post id). Only post_url needs derivation: replace anything
+    # under i.pximg.net (the file URL) with the /artworks/<id> permalink.
+    pixiv_updated = conn.execute(text("""
+        UPDATE post p
+        SET post_url = 'https://www.pixiv.net/artworks/' || p.external_post_id
+        FROM source s
+        WHERE p.source_id = s.id
+          AND s.platform = 'pixiv'
+          AND p.external_post_id IS NOT NULL
+          AND (p.post_url IS NULL
+               OR p.post_url LIKE 'https://i.pximg.net/%'
+               OR p.post_url LIKE 'http://i.pximg.net/%')
+    """)).rowcount
+    print(f"0025: pixiv — backfilled post_url on {pixiv_updated} Posts")
+
+
+def _first_attachment_path(conn, post_id: int) -> str | None:
+    """Return any ImageRecord.path attached to this post (via
+    ImageProvenance). Lowest-id row keeps the migration deterministic
+    so re-running on the same DB picks the same sidecar."""
+    row = conn.execute(
+        text("""
+            SELECT ir.path
+            FROM image_provenance ip
+            JOIN image_record ir ON ir.id = ip.image_record_id
+            WHERE ip.post_id = :pid
+            ORDER BY ip.id ASC
+            LIMIT 1
+        """),
+        {"pid": post_id},
+    ).first()
+    return row[0] if row else None
+
+
+def downgrade() -> None:
+    # Lossy: external_post_id values were overwritten with the correct
+    # post_id; original per-attachment ids weren't preserved. Post-merge
+    # also deleted drop rows. No safe restore. To roll back the schema
+    # invariant, fork from 0024 and re-run sidecar imports.
+    pass
@@ -0,0 +1,53 @@
+"""import_task.recovery_count + refetched — poison-pill circuit breaker
+
+Revision ID: 0026
+Revises: 0025
+Create Date: 2026-05-28
+
+Backs the import-task resilience work (operator-flagged 2026-05-28):
+
+- recovery_count: how many times recover_interrupted_tasks has
+  re-queued this row from a stuck 'processing' state. A row that
+  hard-crashes the worker (OOM / segfault on a corrupt or oversized
+  input) leaves no terminal flip, so the sweep re-queues it — and
+  without a cap it would loop forever, re-crashing the worker each
+  time. After MAX_RECOVERY_ATTEMPTS the sweep marks it 'failed' with a
+  diagnostic instead.
+
+- refetched: whether a one-shot re-download has already been attempted
+  for this task's file. Bounds the Layer-2 re-fetch remediation to a
+  single attempt so source-side corruption doesn't loop.
+
+Both default to 0 / false; additive, no backfill needed.
+"""
+from typing import Sequence, Union
+
+import sqlalchemy as sa
+from alembic import op
+
+revision: str = "0026"
+down_revision: Union[str, None] = "0025"
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    op.add_column(
+        "import_task",
+        sa.Column(
+            "recovery_count", sa.Integer(), nullable=False,
+            server_default="0",
+        ),
+    )
+    op.add_column(
+        "import_task",
+        sa.Column(
+            "refetched", sa.Boolean(), nullable=False,
+            server_default=sa.false(),
+        ),
+    )
+
+
+def downgrade() -> None:
+    op.drop_column("import_task", "refetched")
+    op.drop_column("import_task", "recovery_count")
@@ -0,0 +1,50 @@
+"""drop migration_run — one-and-done GS/IR migration tooling removed
+
+Revision ID: 0027
+Revises: 0026
+Create Date: 2026-05-29
+
+The GS/IR migration tooling (services/migrators, /api/migrate, the
+run_migration task, LegacyMigrationCard, and the MigrationRun model) was
+removed after the migration cutover completed. This drops its now-orphaned
+run-log table. Downgrade recreates the table (mirrors the old model) so the
+migration is reversible.
+"""
+from typing import Sequence, Union
+
+import sqlalchemy as sa
+from alembic import op
+from sqlalchemy.dialects.postgresql import JSONB
+
+revision: str = "0027"
+down_revision: Union[str, None] = "0026"
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    op.drop_table("migration_run")
+
+
+def downgrade() -> None:
+    op.create_table(
+        "migration_run",
+        sa.Column("id", sa.Integer(), primary_key=True),
+        sa.Column("kind", sa.String(length=32), nullable=False),
+        sa.Column("status", sa.String(length=32), nullable=False),
+        sa.Column("dry_run", sa.Boolean(), nullable=False, server_default=sa.false()),
+        sa.Column(
+            "started_at", sa.DateTime(timezone=True), nullable=False,
+            server_default=sa.func.now(),
+        ),
+        sa.Column("finished_at", sa.DateTime(timezone=True), nullable=True),
+        sa.Column(
+            "counts", JSONB(), nullable=False, server_default=sa.text("'{}'::jsonb"),
+        ),
+        sa.Column("error", sa.Text(), nullable=True),
+        sa.Column(
+            "metadata", JSONB(), nullable=False, server_default=sa.text("'{}'::jsonb"),
+        ),
+    )
+    op.create_index("ix_migration_run_kind", "migration_run", ["kind"])
+    op.create_index("ix_migration_run_status", "migration_run", ["status"])
@@ -0,0 +1,190 @@
+"""collapse-sidecar-synthetic: repoint Posts/ImageProvenance/DownloadEvents
+from `sidecar:<platform>:<slug>` synthetic Source anchors onto the real
+Source for the same (artist, platform) when one exists, then delete the
+synthetic.
+
+Revision ID: 0028
+Revises: 0027
+Create Date: 2026-05-31
+
+Background: alembic 0022 (2026-05-26) consolidated the old per-post-URL
+Source rows into one canonical Source per (artist, platform). When NO
+real campaign URL was salvageable among the candidates, it rewrote the
+canonical row to url='sidecar:<platform>:<slug>' enabled=false as a
+disabled anchor for any Posts already attached.
+
+That was fine while it was the only Source for that artist+platform.
+But: the unique constraint on Source is (artist_id, platform, url), not
+(artist_id, platform). When the operator later added the real
+subscription via the UI / extension / etc., a SECOND row landed —
+the real one — with id > the synthetic. Both coexisted.
+
+Two follow-on problems surfaced 2026-05-31:
+
+  1. The Subscriptions UI listed both rows. The synthetic was disabled
+     so the scheduler never polled it, but it looked like a phantom
+     subscription. (Fixed in same commit by SourceService.list filter.)
+  2. importer._source_for_sidecar picked Source by `ORDER BY id ASC
+     LIMIT 1`, so EVERY gallery-dl download since the real Source was
+     added attached its Post to the SYNTHETIC anchor, not the real
+     Source. (Fixed in same commit by preferring non-sidecar URLs.)
+
+This migration is the data half of the cleanup: for every (artist,
+platform) with both a synthetic AND a real Source, repoint the
+synthetic's children (Posts, ImageProvenance, DownloadEvents) onto the
+real Source and delete the synthetic. Reuses the same epid/provenance
+collision dance from alembic 0022 because the same uniqueness
+constraints fire row-by-row during bulk UPDATEs.
+
+Lone synthetic anchors — those where no real Source for the same
+(artist, platform) exists (e.g., filesystem-imported artist with no
+subscription added) — are LEFT INTACT. They anchor real imported
+content; deleting them would CASCADE-delete the Posts the operator
+imported. The SourceService.list filter hides them from the UI; the
+operator can delete them by hand if they want the underlying imports
+gone.
+"""
+from typing import Sequence, Union
+
+from alembic import op
+from sqlalchemy import text
+
+revision: str = "0028"
+down_revision: Union[str, None] = "0027"
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    conn = op.get_bind()
+
+    # Find (artist_id, platform) groups where BOTH a sidecar synthetic
+    # and at least one real Source exist.
+    groups = conn.execute(text("""
+        SELECT artist_id, platform
+        FROM source
+        GROUP BY artist_id, platform
+        HAVING bool_or(url LIKE 'sidecar:%')
+           AND bool_or(url NOT LIKE 'sidecar:%')
+    """)).fetchall()
+
+    for artist_id, platform in groups:
+        rows = conn.execute(
+            text("""
+                SELECT id, url FROM source
+                WHERE artist_id = :a AND platform = :p
+                ORDER BY id ASC
+            """),
+            {"a": artist_id, "p": platform},
+        ).fetchall()
+
+        synthetic_ids = [sid for sid, url in rows if url.startswith("sidecar:")]
+        real_rows = [(sid, url) for sid, url in rows if not url.startswith("sidecar:")]
+        if not synthetic_ids or not real_rows:
+            continue  # belt+suspenders; the GROUP BY already filtered
+
+        # Canonical real: lowest-id non-sidecar Source.
+        canonical_id = real_rows[0][0]
+
+        # STEP A: PRE-merge Post collisions on (canonical, external_post_id).
+        # Mirror alembic 0022's pre-merge logic — when synth has Post X
+        # epid=N and real has Post Y epid=N, the bulk UPDATE below would
+        # trip uq_post_source_external_id row-by-row. Group all Posts
+        # under (canonical + synthetics) by epid; for any group >1,
+        # pick a keep (prefer one already under canonical, else lowest
+        # id) and merge the rest into it.
+        all_posts = conn.execute(
+            text("""
+                SELECT external_post_id, id, source_id
+                FROM post
+                WHERE source_id = :canonical OR source_id = ANY(:synths)
+                ORDER BY external_post_id, id
+            """),
+            {"canonical": canonical_id, "synths": synthetic_ids},
+        ).fetchall()
+        by_epid: dict = {}
+        for epid, post_id, src_id in all_posts:
+            by_epid.setdefault(epid, []).append((post_id, src_id))
+        for _epid, posts in by_epid.items():
+            if len(posts) <= 1:
+                continue
+            canonical_side = [p for p in posts if p[1] == canonical_id]
+            keep_id = canonical_side[0][0] if canonical_side else posts[0][0]
+            drop_ids = [p[0] for p in posts if p[0] != keep_id]
+            for drop_id in drop_ids:
+                # Pre-delete image_provenance rows under drop_ whose
+                # image_record_id already has provenance under keep —
+                # avoids tripping uq_image_provenance_image_post (0021)
+                # row-by-row during the repoint UPDATE.
+                conn.execute(
+                    text("""
+                        DELETE FROM image_provenance
+                        WHERE post_id = :drop_
+                          AND image_record_id IN (
+                              SELECT image_record_id FROM image_provenance
+                              WHERE post_id = :keep
+                          )
+                    """),
+                    {"keep": keep_id, "drop_": drop_id},
+                )
+                conn.execute(
+                    text("""
+                        UPDATE image_provenance SET post_id = :keep
+                        WHERE post_id = :drop_
+                    """),
+                    {"keep": keep_id, "drop_": drop_id},
+                )
+                conn.execute(
+                    text("""
+                        UPDATE image_record SET primary_post_id = :keep
+                        WHERE primary_post_id = :drop_
+                    """),
+                    {"keep": keep_id, "drop_": drop_id},
+                )
+                conn.execute(
+                    text("DELETE FROM post WHERE id = :drop_"),
+                    {"drop_": drop_id},
+                )
+
+        # STEP B: Bulk reparent the remaining Posts off the synthetics.
+        conn.execute(
+            text("""
+                UPDATE post SET source_id = :canonical
+                WHERE source_id = ANY(:synths)
+            """),
+            {"canonical": canonical_id, "synths": synthetic_ids},
+        )
+
+        # STEP C: Reparent ImageProvenance.source_id (denormalized FK;
+        # no UNIQUE on source_id, safe bulk).
+        conn.execute(
+            text("""
+                UPDATE image_provenance SET source_id = :canonical
+                WHERE source_id = ANY(:synths)
+            """),
+            {"canonical": canonical_id, "synths": synthetic_ids},
+        )
+
+        # STEP D: Reparent any DownloadEvent.source_id. Synthetics are
+        # enabled=false so the scheduler never created events for them;
+        # this is belt+suspenders for any rows planted by manual force
+        # or older code paths.
+        conn.execute(
+            text("""
+                UPDATE download_event SET source_id = :canonical
+                WHERE source_id = ANY(:synths)
+            """),
+            {"canonical": canonical_id, "synths": synthetic_ids},
+        )
+
+        # STEP E: Drop the now-empty synthetics.
+        conn.execute(
+            text("DELETE FROM source WHERE id = ANY(:synths)"),
+            {"synths": synthetic_ids},
+        )
+
+
+def downgrade() -> None:
+    # Lossy migration — synthetic Sources deleted, Posts repointed and
+    # potentially merged. No safe downgrade.
+    pass
@@ -0,0 +1,71 @@
+"""drop artist + copyright ml thresholds; lower general default to 0.50
+
+Revision ID: 0029
+Revises: 0028
+Create Date: 2026-06-01
+
+Operator-flagged 2026-06-01: the view modal's Suggestions panel hides
+most general-category predictions because the default threshold is
+0.95. Lowering the default to 0.50 (matches character) so general
+suggestions surface more aggressively; the value remains tunable in
+Settings → ML.
+
+Same change retires two ML suggestion categories whose Tag.kind
+surfaces are unused:
+
+- `artist`: retired in FC-2d-vii-c — artist identity is acquisition-
+  derived (image_record.artist_id), never ML-inferred. The threshold
+  column was a leftover from before that retirement.
+- `copyright`: retired 2026-06-01 — the app uses `fandom` for the
+  franchise/copyright concept (per TagsView.vue's doc comment); no
+  Tag rows of kind=copyright exist, and the threshold column never
+  fed anything user-visible.
+
+Both columns are dropped from ml_settings; the existing row's
+suggestion_threshold_general value is bumped from 0.95 to 0.50 iff
+it's still at the old default, so deployed installs pick up the new
+UX without overriding any operator tuning.
+"""
+from typing import Sequence, Union
+
+from alembic import op
+from sqlalchemy import text
+
+revision: str = "0029"
+down_revision: Union[str, None] = "0028"
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    # Bump the general threshold for installs still at the old default.
+    op.execute(text(
+        "UPDATE ml_settings "
+        "SET suggestion_threshold_general = 0.50 "
+        "WHERE id = 1 AND suggestion_threshold_general = 0.95"
+    ))
+    op.drop_column("ml_settings", "suggestion_threshold_artist")
+    op.drop_column("ml_settings", "suggestion_threshold_copyright")
+
+
+def downgrade() -> None:
+    # Restore the columns with their prior defaults. The bump from
+    # 0.95 → 0.50 isn't reversible without remembering whether the
+    # operator had explicitly set 0.95 (unlikely — that was just the
+    # default) so we leave the current general value as-is.
+    from sqlalchemy import Column, Float
+
+    op.add_column(
+        "ml_settings",
+        Column(
+            "suggestion_threshold_artist",
+            Float, nullable=False, server_default="0.30",
+        ),
+    )
+    op.add_column(
+        "ml_settings",
+        Column(
+            "suggestion_threshold_copyright",
+            Float, nullable=False, server_default="0.50",
+        ),
+    )
@@ -0,0 +1,145 @@
+"""nullable post.source_id + denormalized post.artist_id; retire sidecar synthetics
+
+Revision ID: 0030
+Revises: 0029
+Create Date: 2026-06-01
+
+Operator-asked 2026-06-01 after the Dymkens orphan investigation: the
+sidecar synthetic Source pattern (`sidecar:<platform>:<slug>` rows
+with enabled=false) was technically correct but misled the operator
+into thinking they had phantom subscriptions. The synthetics existed
+solely to satisfy `Post.source_id NOT NULL` for filesystem-imported
+content with no real subscription.
+
+This migration makes the data model honest:
+
+1. **Post gets a denormalized `artist_id` column** so artist filters
+   work without traversing `Post → Source.artist_id`. Backfilled from
+   the existing Source linkage, then NOT NULL'd.
+2. **`Post.source_id` becomes nullable**, FK ondelete `CASCADE` → `SET
+   NULL`. Deleting a Source detaches its Posts instead of destroying
+   imported content (semantically: subscription ends, archive stays).
+3. **`ImageProvenance.source_id` becomes nullable** with the same FK
+   semantic change.
+4. **Sidecar synthetic Sources are deleted** — first NULL out the
+   FKs from Post + ImageProvenance pointing at them (so the implicit
+   CASCADE doesn't fire), then delete. DownloadEvent FK is unchanged
+   (still CASCADE'd, NOT NULL'd) — synthetics have `enabled=false`
+   so no events exist for them.
+
+Uniqueness handling: the existing `uq_post_source_external_id`
+(source_id, external_post_id) keeps working for source-bound Posts
+(Postgres treats NULL != NULL so NULL-source rows aren't deduped by
+it). A second partial unique index covers the NULL-source case on
+(artist_id, external_post_id) so filesystem-imported posts still
+dedupe within an artist.
+"""
+from typing import Sequence, Union
+
+import sqlalchemy as sa
+from alembic import op
+from sqlalchemy import text
+
+revision: str = "0030"
+down_revision: Union[str, None] = "0029"
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    conn = op.get_bind()
+
+    # Step 1: add Post.artist_id, initially nullable for backfill.
+    # FK naming follows the Base.metadata naming_convention
+    # (fk_<table>_<column>_<referred_table>) — alembic 0001 set this up.
+    op.add_column(
+        "post",
+        sa.Column("artist_id", sa.Integer, nullable=True),
+    )
+    op.create_foreign_key(
+        "fk_post_artist_id_artist", "post", "artist",
+        ["artist_id"], ["id"], ondelete="CASCADE",
+    )
+
+    # Step 2: backfill from Source.artist_id (every existing Post has a
+    # Source today, so every row gets populated).
+    conn.execute(text("""
+        UPDATE post p
+        SET artist_id = s.artist_id
+        FROM source s
+        WHERE p.source_id = s.id AND p.artist_id IS NULL
+    """))
+
+    # Sanity: count any remaining NULLs. Should be zero pre-this-migration.
+    remaining = conn.execute(text(
+        "SELECT COUNT(*) FROM post WHERE artist_id IS NULL"
+    )).scalar_one()
+    if remaining:
+        raise RuntimeError(
+            f"alembic 0030: {remaining} post rows have no resolvable "
+            f"artist_id after backfill. Investigate before continuing."
+        )
+
+    # Step 3: enforce NOT NULL + add index for artist-filter queries.
+    op.alter_column("post", "artist_id", nullable=False)
+    op.create_index("ix_post_artist_id", "post", ["artist_id"])
+
+    # Step 4: relax post.source_id + flip FK to SET NULL. The original FK
+    # name from alembic 0001 is `fk_post_source_id_source` per the
+    # NAMING_CONVENTION in models/base.py.
+    op.alter_column("post", "source_id", nullable=True)
+    op.drop_constraint("fk_post_source_id_source", "post", type_="foreignkey")
+    op.create_foreign_key(
+        "fk_post_source_id_source", "post", "source",
+        ["source_id"], ["id"], ondelete="SET NULL",
+    )
+
+    # Step 5: relax image_provenance.source_id + flip FK to SET NULL.
+    op.alter_column("image_provenance", "source_id", nullable=True)
+    op.drop_constraint(
+        "fk_image_provenance_source_id_source", "image_provenance",
+        type_="foreignkey",
+    )
+    op.create_foreign_key(
+        "fk_image_provenance_source_id_source", "image_provenance", "source",
+        ["source_id"], ["id"], ondelete="SET NULL",
+    )
+
+    # Step 6: partial unique index on (artist_id, external_post_id) for
+    # NULL-source Posts. The existing uq_post_source_external_id keeps
+    # guarding source-bound rows; NULL-source rows now dedupe within
+    # an artist.
+    op.execute(
+        "CREATE UNIQUE INDEX uq_post_artist_external_id_null_source "
+        "ON post (artist_id, external_post_id) "
+        "WHERE source_id IS NULL"
+    )
+
+    # Step 7: retire sidecar synthetic Sources. NULL out the references
+    # FIRST (the new FK is SET NULL so CASCADE wouldn't fire anyway, but
+    # being explicit makes the intent clear). Then delete the synthetic
+    # source rows. Any DownloadEvent rows under synthetics CASCADE-die
+    # with the source — synthetics have enabled=false so there shouldn't
+    # be any in practice.
+    conn.execute(text("""
+        UPDATE post
+        SET source_id = NULL
+        WHERE source_id IN (SELECT id FROM source WHERE url LIKE 'sidecar:%')
+    """))
+    conn.execute(text("""
+        UPDATE image_provenance
+        SET source_id = NULL
+        WHERE source_id IN (SELECT id FROM source WHERE url LIKE 'sidecar:%')
+    """))
+    deleted = conn.execute(text(
+        "DELETE FROM source WHERE url LIKE 'sidecar:%' RETURNING id"
+    )).rowcount
+    print(f"alembic 0030: deleted {deleted} sidecar synthetic source rows")
+
+
+def downgrade() -> None:
+    # Lossy migration — the deleted sidecar synthetics can't be
+    # restored from the orphan post.source_id / image_provenance.source_id
+    # values, and the partial unique index encodes a constraint that
+    # NULL-source Posts may now exist. No safe downgrade.
+    pass
@@ -0,0 +1,45 @@
+"""source.backfill_runs_remaining: sticky deep-scan mode
+
+Revision ID: 0031
+Revises: 0030
+Create Date: 2026-06-01
+
+Tick vs backfill mode for subscription downloads. When
+`backfill_runs_remaining > 0`, the next N download runs use
+`skip: True` + 30-min timeout (walk full history). When 0, runs use
+`skip: "exit:20"` + 14.5-min timeout (catch-up mode, exits early once
+20 contiguous archived items are seen).
+
+Operator-flagged 2026-06-01 (Knuxy run #38887): a creator with ~550
+archived posts saturates the 870s catch-up timeout even when there is
+no new content, because gallery-dl's default `skip: True` keeps walking.
+Tick mode short-circuits that; backfill mode is the explicit opt-in for
+deep history scans.
+
+Default 0 (all existing subscriptions start in tick mode).
+"""
+from typing import Sequence, Union
+
+import sqlalchemy as sa
+from alembic import op
+
+revision: str = "0031"
+down_revision: Union[str, None] = "0030"
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    op.add_column(
+        "source",
+        sa.Column(
+            "backfill_runs_remaining",
+            sa.Integer,
+            nullable=False,
+            server_default="0",
+        ),
+    )
+
+
+def downgrade() -> None:
+    op.drop_column("source", "backfill_runs_remaining")
@@ -0,0 +1,41 @@
+"""source.error_type: surface ErrorType taxonomy in FailingSourcesCard
+
+Revision ID: 0032
+Revises: 0031
+Create Date: 2026-06-02
+
+Audit 2026-06-02: the backend computes 13 ErrorType categories (auth_error,
+rate_limited, not_found, access_denied, validation_failed, etc.) and
+stamps each one on DownloadEvent.metadata, but the Source row only carried
+the free-text last_error. Operators couldn't bulk-triage failing sources
+("all auth_error → rotate cookies, all rate_limited → just wait") without
+opening Logs per row.
+
+This column receives the last error_type from _update_source_health
+and gets cleared on a successful run. Nullable + indexed so the failing-
+sources rollup can filter/group cheaply.
+"""
+from typing import Sequence, Union
+
+import sqlalchemy as sa
+from alembic import op
+
+revision: str = "0032"
+down_revision: Union[str, None] = "0031"
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    op.add_column(
+        "source",
+        sa.Column("error_type", sa.String(length=32), nullable=True),
+    )
+    op.create_index(
+        "ix_source_error_type", "source", ["error_type"],
+    )
+
+
+def downgrade() -> None:
+    op.drop_index("ix_source_error_type", table_name="source")
+    op.drop_column("source", "error_type")
@@ -0,0 +1,48 @@
+"""suggestion_threshold default 0.50 → 0.70
+
+Revision ID: 0033
+Revises: 0032
+Create Date: 2026-06-02
+
+Operator-flagged 2026-06-02 — the 0.50 default (set on 2026-06-01) is
+too noisy in practice; raise to 0.70 for both suggestion categories.
+
+Only conditionally updates singletons whose current value is still the
+2026-06-01 default (0.50). Operators who deliberately tuned their row
+to some other value (0.55, 0.65, 0.80, etc. via the Settings UI) keep
+their pick — the migration only catches the unchanged-default case.
+"""
+from typing import Sequence, Union
+
+from alembic import op
+
+revision: str = "0033"
+down_revision: Union[str, None] = "0032"
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    op.execute(
+        "UPDATE ml_settings "
+        "SET suggestion_threshold_character = 0.70 "
+        "WHERE id = 1 AND suggestion_threshold_character = 0.50"
+    )
+    op.execute(
+        "UPDATE ml_settings "
+        "SET suggestion_threshold_general = 0.70 "
+        "WHERE id = 1 AND suggestion_threshold_general = 0.50"
+    )
+
+
+def downgrade() -> None:
+    op.execute(
+        "UPDATE ml_settings "
+        "SET suggestion_threshold_character = 0.50 "
+        "WHERE id = 1 AND suggestion_threshold_character = 0.70"
+    )
+    op.execute(
+        "UPDATE ml_settings "
+        "SET suggestion_threshold_general = 0.50 "
+        "WHERE id = 1 AND suggestion_threshold_general = 0.70"
+    )
@@ -3,13 +3,23 @@
 import logging
 from pathlib import Path

-from quart import Quart
+from quart import Quart, request

 from .api import all_blueprints
 from .config import get_config
 from .frontend import frontend_bp
 from .services.credential_crypto import CredentialCrypto

+# Browser-extension origins. The FabledCurator extension fetches from
+# moz-extension://<uuid>/ on Firefox and chrome-extension://<uuid>/ on
+# Chromium-based browsers. Operator-flagged 2026-05-26: extension's
+# 'Test connection' returned `NetworkError` because the X-Extension-Key
+# header on /api/credentials triggers a CORS preflight that our routes
+# don't handle. Whitelisting only these two schemes (not opening CORS
+# up generally) lets the extension talk to a plain-HTTP self-hosted FC
+# without weakening the no-CORS posture for normal browser usage.
+_EXTENSION_ORIGIN_SCHEMES = ("moz-extension://", "chrome-extension://")
+
 _CREDENTIAL_KEY_PATH = Path("/images/secrets/credential_key.b64")


@@ -23,18 +33,39 @@ def create_app() -> Quart:

    app = Quart(__name__)
    app.secret_key = cfg.secret_key
-    # FC-5: legacy IR ingest JSON can run to tens of MB (hundreds of
-    # thousands of image_tag_associations). Werkzeug's default form
-    # memory cap is 500KB; raise both ceilings so the multipart upload
-    # for /api/migrate/ir_ingest doesn't 413.
-    app.config["MAX_CONTENT_LENGTH"] = 1024 * 1024 * 1024   # 1 GB
-    app.config["MAX_FORM_MEMORY_SIZE"] = 1024 * 1024 * 1024  # 1 GB

    for bp in all_blueprints():
        app.register_blueprint(bp)
    # Registered last so /api/* routes win over the SPA catch-all.
    app.register_blueprint(frontend_bp)

+    @app.before_request
+    async def _extension_cors_preflight():
+        # Short-circuit OPTIONS preflight from the browser extension with a
+        # 204 + CORS headers (the after_request hook below adds them).
+        # Without this, OPTIONS lands on routes that only declared POST/GET
+        # methods and 405s before the after_request gets a chance.
+        if request.method != "OPTIONS":
+            return None
+        origin = request.headers.get("Origin", "")
+        if any(origin.startswith(s) for s in _EXTENSION_ORIGIN_SCHEMES):
+            return "", 204
+        return None
+
+    @app.after_request
+    async def _extension_cors_headers(response):
+        origin = request.headers.get("Origin", "")
+        if any(origin.startswith(s) for s in _EXTENSION_ORIGIN_SCHEMES):
+            response.headers["Access-Control-Allow-Origin"] = origin
+            response.headers["Access-Control-Allow-Methods"] = (
+                "GET, POST, PATCH, DELETE, OPTIONS"
+            )
+            response.headers["Access-Control-Allow-Headers"] = (
+                "Content-Type, X-Extension-Key"
+            )
+            response.headers["Access-Control-Max-Age"] = "86400"
+        return response
+
    @app.after_serving
    async def _dispose_db_engine() -> None:
        from .extensions import dispose_engine
@@ -26,7 +26,6 @@ def all_blueprints() -> list[Blueprint]:
    from .extension import extension_bp
    from .gallery import gallery_bp
    from .import_admin import import_admin_bp
-    from .migrate import migrate_bp
    from .ml_admin import ml_admin_bp
    from .platforms import platforms_bp
    from .posts import posts_bp
@@ -54,7 +53,6 @@ def all_blueprints() -> list[Blueprint]:
        admin_bp,
        cleanup_bp,
        import_admin_bp,
-        migrate_bp,
        suggestions_bp,
        allowlist_bp,
        aliases_bp,
@@ -0,0 +1,16 @@
+"""Shared API response helpers."""
+
+from quart import jsonify
+
+
+def error_response(
+    error: str, *, status: int = 400, detail: str | None = None, **extra,
+):
+    """JSON error body + HTTP status. `detail` is included only when given;
+    `extra` keys are merged into the body. Returns the (response, status)
+    tuple Quart expects. Imported as `_bad` by the blueprints."""
+    body = {"error": error}
+    if detail is not None:
+        body["detail"] = detail
+    body.update(extra)
+    return jsonify(body), status
@@ -6,6 +6,7 @@ Five action surfaces:
  DELETE /api/admin/tags/<int:tag_id>              (Tier B)
  POST   /api/admin/tags/<int:dest_id>/merge       (Tier B)
  POST   /api/admin/tags/prune-unused              (Tier A)
+  POST   /api/admin/tags/purge-legacy              (Tier A)
  GET    /api/admin/tags/<int:tag_id>/usage-count  (helper)

 Tier-C ops take a dry_run body flag (returns projection inline,
@@ -23,16 +24,11 @@ from sqlalchemy import select
 from ..extensions import get_session
 from ..models import Artist
 from ..services.cleanup_service import project_artist_cascade, project_bulk_image_delete
+from ._responses import error_response as _bad

 admin_bp = Blueprint("admin", __name__, url_prefix="/api/admin")


-def _bad(error: str, *, status: int = 400, **extra):
-    body = {"error": error}
-    body.update(extra)
-    return jsonify(body), status
-
-
 def _bulk_image_confirm_token(image_ids: list[int]) -> str:
    """Stable 8-hex token derived from the sorted id list. Mutates
    when the selection changes; stays the same across modal opens of
@@ -97,11 +93,19 @@ async def images_bulk_delete():
            )
        )

-    if dry_run:
-        return jsonify(projected)
-
    sha8 = _bulk_image_confirm_token(image_ids)
    expected = f"delete-images-{sha8}"
+
+    if dry_run:
+        # Hand the canonical Tier-C confirm token back with the
+        # projection so the frontend doesn't have to recompute SHA-256
+        # client-side via crypto.subtle (Secure-Context-gated,
+        # undefined on plain-HTTP origins per the homelab posture).
+        # Operator-flagged 2026-05-27.
+        projected["confirm_token"] = expected
+        return jsonify(projected)
+
+
    if supplied_confirm != expected:
        return _bad(
            "confirm_mismatch",
@@ -198,3 +202,23 @@ async def tags_prune_unused():
            )
        )
    return jsonify(result)
+
+
+@admin_bp.route("/tags/purge-legacy", methods=["POST"])
+async def tags_purge_legacy():
+    """Tier-A: delete legacy IR-migration tags — archive/post/artist
+    kinds (e.g. `BlenderKnight:Hannah_BJ_Loops`) PLUS general tags with
+    a legacy name prefix (`source:*`, from IR's source kind that fell
+    back to general). dry-run preview returns per-kind + per-prefix
+    counts + a sample so the UI shows exactly what'll go before the
+    operator confirms with dry_run=false."""
+    from ..services.cleanup_service import purge_legacy_tags
+
+    body = await request.get_json(silent=True) or {}
+    dry_run = bool(body.get("dry_run", False))
+
+    async with get_session() as session:
+        result = await session.run_sync(
+            lambda sync_sess: purge_legacy_tags(sync_sess, dry_run=dry_run)
+        )
+    return jsonify(result)
@@ -31,18 +31,13 @@ from sqlalchemy import select
 from ..extensions import get_session
 from ..models import LibraryAuditRun
 from ..services import cleanup_service
+from ._responses import error_response as _bad

 cleanup_bp = Blueprint("cleanup", __name__, url_prefix="/api/cleanup")

 IMAGES_ROOT = Path("/images")


-def _bad(error: str, *, status: int = 400, **extra):
-    body = {"error": error}
-    body.update(extra)
-    return jsonify(body), status
-
-
 def _min_dim_token(min_w: int, min_h: int) -> str:
    # SHA-256 (not MD5) — Web Crypto's subtle.digest rejects MD5; both
    # sides use SHA-256 truncated to 8 hex chars.
@@ -81,6 +76,13 @@ async def min_dim_preview():
                s, min_width=min_w, min_height=min_h,
            )
        )
+    # Hand the canonical Tier-C delete token back with the preview so
+    # the frontend doesn't have to recompute SHA-256 client-side.
+    # window.crypto.subtle is Secure-Context-gated and undefined on
+    # plain-HTTP origins (homelab posture); without this the Delete
+    # button silently swallowed the TypeError and never opened the
+    # confirm modal. Operator-flagged 2026-05-27.
+    projection["confirm_token"] = _min_dim_token(min_w, min_h)
    return jsonify(projection)


@@ -20,6 +20,7 @@ from ..services.credential_service import (
    UnknownPlatformError,
    WrongAuthTypeError,
 )
+from ._responses import error_response as _bad

 credentials_bp = Blueprint("credentials", __name__, url_prefix="/api/credentials")

@@ -38,14 +39,6 @@ def _get_crypto() -> CredentialCrypto:
    return _crypto


-def _bad(error: str, *, status: int = 400, detail: str | None = None, **extra):
-    body = {"error": error}
-    if detail is not None:
-        body["detail"] = detail
-    body.update(extra)
-    return jsonify(body), status
-
-
 async def _ext_key_ok(session) -> bool:
    """If X-Extension-Key is supplied, it must match the stored value.
    Missing header → True (browser path; accepted per homelab posture).
@@ -124,3 +117,56 @@ async def delete_credential(platform: str):
        except LookupError:
            return _bad("not_found", status=404)
    return "", 204
+
+
+@credentials_bp.route("/<platform>/verify", methods=["POST"])
+async def verify_credential(platform: str):
+    """Test the stored credential by running gallery-dl --simulate
+    against one of the platform's enabled sources. On success stamps
+    last_verified. Returns {valid: bool|null, reason, last_verified?}.
+    valid=null means "couldn't test" (no credential, or no enabled
+    source to point at)."""
+    from ..models import Artist, Source
+    from ..services.gallery_dl import GalleryDLService, SourceConfig
+
+    async with get_session() as session:
+        if not await _ext_key_ok(session):
+            return _bad("unauthorized", status=401)
+        svc = CredentialService(session, _get_crypto())
+        record = await svc.get(platform)
+        if record is None:
+            return jsonify({"valid": None, "reason": "No credential stored for this platform."})
+
+        # Pick an enabled source for this platform to point the probe at.
+        row = (await session.execute(
+            select(Source, Artist)
+            .join(Artist, Artist.id == Source.artist_id)
+            .where(Source.platform == platform, Source.enabled.is_(True))
+            .order_by(Source.id.asc())
+        )).first()
+        if row is None:
+            return jsonify({
+                "valid": None,
+                "reason": "No enabled source for this platform to verify against — add a subscription first.",
+            })
+        source, artist = row
+
+        cookies_path = await svc.get_cookies_path(platform)
+        auth_token = await svc.get_token(platform)
+
+    gdl = GalleryDLService(images_root=Path("/images"))
+    ok, message = await gdl.verify(
+        url=source.url,
+        artist_slug=artist.slug,
+        platform=platform,
+        source_config=SourceConfig.from_dict(source.config_overrides or {}),
+        cookies_path=str(cookies_path) if cookies_path else None,
+        auth_token=auth_token,
+    )
+
+    last_verified = None
+    if ok:
+        async with get_session() as session:
+            ts = await CredentialService(session, _get_crypto()).mark_verified(platform)
+            last_verified = ts.isoformat() if ts else None
+    return jsonify({"valid": ok, "reason": message, "last_verified": last_verified})
@@ -5,8 +5,10 @@ status/source/artist. Returns slim records.
 Detail view: full DownloadEvent including the metadata JSONB.
 """

+from datetime import UTC, datetime, timedelta
+
 from quart import Blueprint, jsonify, request
-from sqlalchemy import select
+from sqlalchemy import func, select

 from ..extensions import get_session
 from ..models import Artist, DownloadEvent, Source
@@ -95,6 +97,83 @@ async def list_downloads():
    return jsonify([_list_record(e, s, a) for e, s, a in rows])


+@downloads_bp.route("/stats", methods=["GET"])
+async def downloads_stats():
+    """Status-grouped count over download_event for the dashboard stat chips.
+
+    `?window_hours=` (default 24) bounds by `started_at`. The full set of
+    statuses is always present in the response (zero for missing) so the
+    UI doesn't have to fill in defaults.
+    """
+    try:
+        window_hours = int(request.args.get("window_hours", "24"))
+    except ValueError:
+        return jsonify({"error": "invalid_window_hours"}), 400
+    if window_hours < 1 or window_hours > 24 * 365:
+        return jsonify({"error": "invalid_window_hours"}), 400
+
+    since = datetime.now(UTC) - timedelta(hours=window_hours)
+    out = {"pending": 0, "running": 0, "ok": 0, "error": 0, "skipped": 0}
+    async with get_session() as session:
+        stmt = (
+            select(DownloadEvent.status, func.count())
+            .where(DownloadEvent.started_at >= since)
+            .group_by(DownloadEvent.status)
+        )
+        for status, n in (await session.execute(stmt)).all():
+            if status in out:
+                out[status] = int(n)
+    return jsonify(out)
+
+
+@downloads_bp.route("/activity", methods=["GET"])
+async def downloads_activity():
+    """Hourly download-event counts over the last `?hours=` (default 24).
+
+    Returns a fixed-length, oldest-first bucket array so the UI can render
+    a sparkline directly. Bucketing is done in Python against UTC to dodge
+    session-timezone ambiguity in SQL date_trunc.
+    """
+    try:
+        hours = int(request.args.get("hours", "24"))
+    except ValueError:
+        return jsonify({"error": "invalid_hours"}), 400
+    hours = max(1, min(168, hours))
+
+    now = datetime.now(UTC)
+    end = now.replace(minute=0, second=0, microsecond=0)
+    start = end - timedelta(hours=hours - 1)
+    buckets = [
+        {"hour": (start + timedelta(hours=i)).isoformat(),
+         "ok": 0, "error": 0, "other": 0, "total": 0}
+        for i in range(hours)
+    ]
+
+    async with get_session() as session:
+        rows = (await session.execute(
+            select(DownloadEvent.started_at, DownloadEvent.status)
+            .where(DownloadEvent.started_at >= start)
+        )).all()
+
+    for started_at, status in rows:
+        if started_at is None:
+            continue
+        sa = started_at if started_at.tzinfo else started_at.replace(tzinfo=UTC)
+        idx = int((sa - start).total_seconds() // 3600)
+        if not (0 <= idx < hours):
+            continue
+        b = buckets[idx]
+        if status == "ok":
+            b["ok"] += 1
+        elif status == "error":
+            b["error"] += 1
+        else:
+            b["other"] += 1
+        b["total"] += 1
+
+    return jsonify({"hours": hours, "buckets": buckets})
+
+
@downloads_bp.route("/<int:event_id>", methods=["GET"])
 async def get_download(event_id: int):
    async with get_session() as session:
@@ -108,3 +187,20 @@ async def get_download(event_id: int):
            return jsonify({"error": "not_found"}), 404
        event, source, artist = row
    return jsonify(_detail_record(event, source, artist))
+
+
+@downloads_bp.route("/recover-stalled", methods=["POST"])
+async def recover_stalled():
+    """Trigger the recover_stalled_download_events sweep on demand.
+
+    The same sweep runs every 5 min via Beat (see celery_app.beat_schedule);
+    this endpoint exists so the operator can force-clear stuck pending/
+    running download_events from the Subscriptions → Downloads maintenance
+    menu without waiting for the next scheduled tick.
+    """
+    # Local import: avoids registering maintenance tasks during blueprint
+    # import (Celery task discovery races with the API import otherwise).
+    from ..tasks.maintenance import recover_stalled_download_events
+
+    recover_stalled_download_events.delay()
+    return jsonify({"queued": True}), 202
@@ -20,6 +20,7 @@ from ..services.extension_service import (
    UnknownPlatformError,
 )
 from ..services.source_service import KNOWN_PLATFORMS
+from ._responses import error_response as _bad

 extension_bp = Blueprint("extension", __name__, url_prefix="/api/extension")

@@ -30,12 +31,6 @@ XPI_DIR = Path("/app/frontend/dist/extension")
 _XPI_VERSION_RE = re.compile(r"fabledcurator-(?P<version>[\w.-]+)\.xpi$")


-def _bad(error: str, *, status: int = 400, **extra):
-    body = {"error": error}
-    body.update(extra)
-    return jsonify(body), status
-
-
 async def _ext_key_required(session) -> bool:
    """Unlike /api/credentials (which accepts the browser path with no
    header), quick-add-source writes server state and must be explicitly
@@ -62,6 +57,24 @@ def _sha256(path: Path) -> str:
    return h.hexdigest()


+@extension_bp.route("/probe", methods=["GET"])
+async def probe_source():
+    """Read-only resolution of a creator-page URL: tells the extension
+    whether this URL is already a Source, is for an Artist that exists
+    but with a different URL, is brand new, or doesn't match any known
+    platform pattern. Drives the content-script chip's color/copy
+    BEFORE the operator clicks, so the button can show 'already added'
+    without requiring an add-attempt."""
+    url = (request.args.get("url") or "").strip()
+    if not url:
+        return _bad("invalid_body", detail="url query parameter is required")
+    async with get_session() as session:
+        if not await _ext_key_required(session):
+            return _bad("unauthorized", status=401)
+        result = await ExtensionService(session).probe(url)
+    return jsonify(result)
+
+
@extension_bp.route("/quick-add-source", methods=["POST"])
 async def quick_add_source():
    body = await request.get_json(silent=True)
@@ -43,7 +43,6 @@ async def scroll():
                    "height": i.height,
                    "created_at": i.created_at.isoformat(),
                    "posted_at": i.posted_at.isoformat() if i.posted_at else None,
-                    "effective_date": i.effective_date.isoformat(),
                    "thumbnail_url": i.thumbnail_url,
                    "artist": i.artist,
                }
@@ -35,10 +35,26 @@ async def trigger_scan():
@import_admin_bp.route("/status", methods=["GET"])
 async def status():
    async with get_session() as session:
+        # Active batch = running batch that still has outstanding work.
+        # Plain "most recent running" picks freshly-created scans that
+        # enqueued zero new files and hides the older batch that's
+        # actually being processed. Mirrors the EXISTS predicate
+        # /api/system/stats already uses (api/settings.py:145-160).
+        # Audit 2026-06-02 — /api/import/status and /api/system/stats
+        # used to disagree on the active-batch predicate; the UI banner
+        # said "Scanning…" indefinitely while the stats card said idle.
        active = (
            await session.execute(
                select(ImportBatch)
-                .where(ImportBatch.status == "running")
+                .where(
+                    ImportBatch.status == "running",
+                    select(ImportTask.id)
+                    .where(
+                        ImportTask.batch_id == ImportBatch.id,
+                        ImportTask.status.in_(["pending", "queued", "processing"]),
+                    )
+                    .exists(),
+                )
                .order_by(ImportBatch.started_at.desc())
                .limit(1)
            )
@@ -114,18 +130,53 @@ async def retry_failed():
                status="queued", error=None,
                started_at=None, finished_at=None,
            )
-            .returning(ImportTask.id)
+            .returning(ImportTask.id, ImportTask.task_type)
        )
-        failed_ids = [row[0] for row in result.all()]
-        if not failed_ids:
+        failed = result.all()
+        if not failed:
            return jsonify({"retried": 0})
        await session.commit()

-    from ..tasks.import_file import import_media_file
-    for tid in failed_ids:
-        import_media_file.delay(tid)
+    from ..tasks.import_file import enqueue_import
+    for tid, task_type in failed:
+        enqueue_import(tid, task_type)

-    return jsonify({"retried": len(failed_ids)})
+    return jsonify({"retried": len(failed)})
+
+
+@import_admin_bp.route("/tasks/<int:task_id>/refetch", methods=["POST"])
+async def refetch_task(task_id: int):
+    """Layer-2 one-shot re-download: delete the (corrupt) file behind a
+    failed import task and re-run its source's downloader to fetch a
+    fresh copy. Only works for files that resolve to an enabled,
+    real-URL subscription Source; filesystem-only imports return
+    no_source.
+
+    Returns one of: refetch_queued (+source_id) / no_source /
+    already_refetched / not_found / not_failed.
+    """
+    async with get_session() as session:
+        result = await session.run_sync(_refetch_task_sync, task_id)
+    if result["status"] == "not_found":
+        return jsonify(result), 404
+    if result["status"] == "not_failed":
+        return jsonify(result), 400
+    return jsonify(result)
+
+
+def _refetch_task_sync(session, task_id: int) -> dict:
+    from pathlib import Path
+
+    from ..models import ImportSettings
+    from ..services.refetch_service import attempt_refetch
+
+    task = session.get(ImportTask, task_id)
+    if task is None:
+        return {"status": "not_found"}
+    if task.status != "failed":
+        return {"status": "not_failed"}
+    settings = ImportSettings.load_sync(session)
+    return attempt_refetch(session, task, Path(settings.import_scan_path))


@import_admin_bp.route("/clear-stuck", methods=["POST"])
@@ -1,112 +0,0 @@
-"""FC-5: /api/migrate — trigger and poll migration runs.
-
-Ingest kinds (gs_ingest, ir_ingest) accept multipart/form-data with an
-`export_file` field. All other kinds accept JSON. Backup + rollback
-were retired in FC-3h (2026-05-24); use /api/system/backup/* instead.
-"""
-
-import json
-
-from quart import Blueprint, jsonify, request
-from sqlalchemy import select
-
-from ..extensions import get_session
-from ..models import MigrationRun
-from ..tasks.migration import run_migration
-
-migrate_bp = Blueprint("migrate", __name__, url_prefix="/api/migrate")
-
-# 'backup' + 'rollback' retired 2026-05-24 (FC-3h); see /api/system/backup/*.
-_VALID_KINDS = frozenset({
-    "gs_ingest", "ir_ingest", "tag_apply",
-    "ml_queue", "verify", "cleanup",
-})
-_INGEST_KINDS = frozenset({"gs_ingest", "ir_ingest"})
-
-
-def _bad(error: str, *, status: int = 400, **extra):
-    body = {"error": error}
-    body.update(extra)
-    return jsonify(body), status
-
-
-def _run_to_dict(run: MigrationRun) -> dict:
-    return {
-        "id": run.id,
-        "kind": run.kind,
-        "status": run.status,
-        "dry_run": run.dry_run,
-        "started_at": run.started_at.isoformat(),
-        "finished_at": run.finished_at.isoformat() if run.finished_at else None,
-        "counts": run.counts or {},
-        "error": run.error,
-        "metadata": run.metadata_ or {},
-    }
-
-
-@migrate_bp.route("/<kind>", methods=["POST"])
-async def create_run(kind: str):
-    if kind not in _VALID_KINDS:
-        return _bad("unknown_kind", detail=f"kind must be one of {sorted(_VALID_KINDS)}")
-
-    # Ingest kinds accept multipart/form-data; everything else takes JSON.
-    if kind in _INGEST_KINDS:
-        form = await request.form
-        files = await request.files
-        if "export_file" not in files:
-            return _bad("missing_export_file", detail="multipart export_file required")
-        export_file = files["export_file"]
-        try:
-            raw = export_file.read()
-            data = json.loads(raw.decode("utf-8"))
-        except (UnicodeDecodeError, json.JSONDecodeError) as exc:
-            return _bad("invalid_export_file", detail=str(exc))
-        dry_run = str(form.get("dry_run", "false")).lower() in ("true", "1", "yes")
-        params: dict = {"data": data, "dry_run": dry_run}
-    else:
-        body = await request.get_json()
-        if body is None:
-            body = {}
-        if not isinstance(body, dict):
-            return _bad("invalid_body")
-        dry_run = bool(body.get("dry_run", False))
-        params = dict(body)
-
-    async with get_session() as session:
-        run = MigrationRun(kind=kind, status="pending", dry_run=dry_run)
-        session.add(run)
-        await session.commit()
-        await session.refresh(run)
-        run_id = run.id
-
-    run_migration.delay(run_id, kind, params)
-    return jsonify({"run_id": run_id, "status": "pending"}), 202
-
-
-@migrate_bp.route("/runs/<int:run_id>", methods=["GET"])
-async def get_run(run_id: int):
-    async with get_session() as session:
-        run = (await session.execute(
-            select(MigrationRun).where(MigrationRun.id == run_id)
-        )).scalar_one_or_none()
-    if run is None:
-        return _bad("not_found", status=404)
-    return jsonify(_run_to_dict(run))
-
-
-@migrate_bp.route("/runs", methods=["GET"])
-async def list_runs():
-    try:
-        limit = int(request.args.get("limit", "10"))
-    except ValueError:
-        return _bad("invalid_limit")
-    if limit < 1 or limit > 100:
-        return _bad("invalid_limit")
-
-    async with get_session() as session:
-        rows = (await session.execute(
-            select(MigrationRun)
-            .order_by(MigrationRun.id.desc())
-            .limit(limit)
-        )).scalars().all()
-    return jsonify([_run_to_dict(r) for r in rows])
@@ -9,9 +9,7 @@ ml_admin_bp = Blueprint("ml_admin", __name__, url_prefix="/api/ml")


 _EDITABLE = (
-    "suggestion_threshold_artist",
    "suggestion_threshold_character",
-    "suggestion_threshold_copyright",
    "suggestion_threshold_general",
    "centroid_similarity_threshold",
    "min_reference_images",
@@ -28,9 +26,7 @@ async def get_settings():
        ).scalar_one()
    return jsonify(
        {
-            "suggestion_threshold_artist": s.suggestion_threshold_artist,
            "suggestion_threshold_character": s.suggestion_threshold_character,
-            "suggestion_threshold_copyright": s.suggestion_threshold_copyright,
            "suggestion_threshold_general": s.suggestion_threshold_general,
            "centroid_similarity_threshold": s.centroid_similarity_threshold,
            "min_reference_images": s.min_reference_images,
@@ -5,18 +5,11 @@ from quart import Blueprint, jsonify, request
 from ..extensions import get_session
 from ..services.post_feed_service import PostFeedService
 from ..services.source_service import KNOWN_PLATFORMS
+from ._responses import error_response as _bad

 posts_bp = Blueprint("posts", __name__, url_prefix="/api/posts")


-def _bad(error: str, *, status: int = 400, detail: str | None = None, **extra):
-    body = {"error": error}
-    if detail is not None:
-        body["detail"] = detail
-    body.update(extra)
-    return jsonify(body), status
-
-
@posts_bp.route("", methods=["GET"])
 async def list_posts():
    args = request.args
@@ -25,6 +18,8 @@ async def list_posts():
    artist_id_raw = args.get("artist_id")
    platform = args.get("platform") or None
    limit_raw = args.get("limit", "24")
+    direction = args.get("direction", "older")
+    around_raw = args.get("around")

    try:
        limit = int(limit_raw)
@@ -33,6 +28,16 @@ async def list_posts():
    if limit < 1 or limit > 100:
        return _bad("invalid_limit", detail="limit must be between 1 and 100")

+    if direction not in ("older", "newer"):
+        return _bad("invalid_direction", detail="direction must be 'older' or 'newer'")
+
+    around_id = None
+    if around_raw is not None:
+        try:
+            around_id = int(around_raw)
+        except ValueError:
+            return _bad("invalid_around", detail="around must be an integer post id")
+
    artist_id = None
    if artist_id_raw is not None:
        try:
@@ -47,11 +52,20 @@ async def list_posts():
        )

    async with get_session() as session:
-        try:
-            page = await PostFeedService(session).scroll(
-                cursor=cursor, artist_id=artist_id,
+        svc = PostFeedService(session)
+        if around_id is not None:
+            result = await svc.around(
+                post_id=around_id, artist_id=artist_id,
                platform=platform, limit=limit,
            )
+            if result is None:
+                return _bad("not_found", status=404, detail=f"post id={around_id}")
+            return jsonify(result)
+        try:
+            page = await svc.scroll(
+                cursor=cursor, artist_id=artist_id,
+                platform=platform, limit=limit, direction=direction,
+            )
        except ValueError as exc:
            # Service raises ValueError for malformed cursors only;
            # limit bounds are validated above.
@@ -31,9 +31,7 @@ _EDITABLE_FIELDS = (
@settings_bp.route("/settings/import", methods=["GET"])
 async def get_import_settings():
    async with get_session() as session:
-        row = (
-            await session.execute(select(ImportSettings).where(ImportSettings.id == 1))
-        ).scalar_one()
+        row = await ImportSettings.load(session)
    return jsonify({
        "min_width": row.min_width,
        "min_height": row.min_height,
@@ -99,9 +97,7 @@ async def update_import_settings():
            return _bad_int("download_failure_warning_threshold", 1, 100)

    async with get_session() as session:
-        row = (
-            await session.execute(select(ImportSettings).where(ImportSettings.id == 1))
-        ).scalar_one()
+        row = await ImportSettings.load(session)
        for field in _EDITABLE_FIELDS:
            if field in body:
                setattr(row, field, body[field])
@@ -5,6 +5,7 @@ from sqlalchemy import select

 from ..extensions import get_session
 from ..models import DownloadEvent, Source
+from ..services.scheduler_service import active_platform_cooldowns, scheduler_status
 from ..services.source_service import (
    KNOWN_PLATFORMS,
    ArtistNotFoundError,
@@ -14,18 +15,11 @@ from ..services.source_service import (
    SourceService,
    UnknownPlatformError,
 )
+from ._responses import error_response as _bad

 sources_bp = Blueprint("sources", __name__, url_prefix="/api/sources")


-def _bad(error: str, *, status: int = 400, detail: str | None = None, **extra):
-    body = {"error": error}
-    if detail is not None:
-        body["detail"] = detail
-    body.update(extra)
-    return jsonify(body), status
-
-
@sources_bp.route("", methods=["GET"])
 async def list_sources():
    artist_id_raw = request.args.get("artist_id")
@@ -35,11 +29,19 @@ async def list_sources():
            artist_id = int(artist_id_raw)
        except ValueError:
            return _bad("invalid_artist_id", detail="artist_id must be an integer")
+    failing = request.args.get("failing", "").lower() in ("1", "true", "yes")
    async with get_session() as session:
-        records = await SourceService(session).list(artist_id=artist_id)
+        records = await SourceService(session).list(artist_id=artist_id, failing=failing)
    return jsonify([r.to_dict() for r in records])


+@sources_bp.route("/schedule-status", methods=["GET"])
+async def schedule_status():
+    """FC-dashboards: scheduler health for the Subscriptions hub."""
+    async with get_session() as session:
+        return jsonify(await scheduler_status(session))
+
+
@sources_bp.route("/<int:source_id>", methods=["GET"])
 async def get_source(source_id: int):
    async with get_session() as session:
@@ -118,12 +120,46 @@ async def delete_source(source_id: int):
    return "", 204


+@sources_bp.route("/<int:source_id>/backfill", methods=["POST"])
+async def set_backfill(source_id: int):
+    """Plan #544: arm a source for backfill mode for the next N download
+    runs. Body: `{"runs": int}` (1..10, default 3). Returns the updated
+    source dict. While backfill_runs_remaining > 0, downloads use
+    gallery-dl's full-walk config (skip: True + 30-min timeout) instead
+    of the catch-up default (skip: "exit:20" + 14.5-min timeout)."""
+    payload = await request.get_json(silent=True) or {}
+    runs = payload.get("runs", 3)
+    try:
+        runs = int(runs)
+    except (TypeError, ValueError):
+        return _bad("invalid_runs", detail="runs must be an integer")
+    async with get_session() as session:
+        try:
+            record = await SourceService(session).set_backfill_runs(
+                source_id, runs,
+            )
+        except LookupError:
+            return _bad("not_found", status=404)
+        except ValueError as exc:
+            return _bad("invalid_runs", detail=str(exc))
+    return jsonify(record.to_dict())
+
+
@sources_bp.route("/<int:source_id>/check", methods=["POST"])
 async def check_source(source_id: int):
    """FC-3c: enqueue a download for this source.

    Returns 202 with the new DownloadEvent id. If a pending/running
-    event already exists for this source, returns 409 with that id."""
+    event already exists for this source, returns 409 with that id. If
+    the source's platform is currently in a rate-limit cooldown, returns
+    **202 with `{status: "deferred", cooldown_until, platform}`** and
+    does NOT create an event or dispatch — the bulk retry path uses this
+    to avoid bowling N sources right back into the rate limit the
+    cooldown is preventing. Single-click "retry this one source" passes
+    `?force=true` to override the cooldown (operator-explicit, useful
+    for rapid auth-fix testing). The in-flight guard always applies.
+    """
+    force = (request.args.get("force") or "").lower() in ("1", "true", "yes")
    async with get_session() as session:
        source = (await session.execute(
            select(Source).where(Source.id == source_id)
@@ -133,6 +169,19 @@ async def check_source(source_id: int):
        if not source.enabled:
            return _bad("source_disabled", detail="enable the source first")

+        # Cooldown gate (unless explicitly overridden). Checked before the
+        # in-flight guard because a deferred retry doesn't need to create
+        # or check for an event at all.
+        if not force:
+            cooldowns = await active_platform_cooldowns(session)
+            expires_at = cooldowns.get(source.platform)
+            if expires_at is not None:
+                return jsonify({
+                    "status": "deferred",
+                    "platform": source.platform,
+                    "cooldown_until": expires_at.isoformat(),
+                }), 202
+
        in_flight = (await session.execute(
            select(DownloadEvent.id).where(
                DownloadEvent.source_id == source_id,
@@ -20,6 +20,7 @@ from sqlalchemy import desc, func, select
 from ..config import get_config
 from ..extensions import get_session
 from ..models import TaskRun
+from ..services.scheduler_service import scheduler_status

 system_activity_bp = Blueprint(
    "system_activity", __name__, url_prefix="/api/system/activity",
@@ -81,17 +82,22 @@ def _read_workers_sync() -> dict:
    }


+async def _queues_cached() -> dict:
+    """Per-queue Redis LLEN, cached 2s. Shared by /queues and /summary."""
+    now = time.time()
+    if _QUEUE_CACHE["data"] is None or (now - _QUEUE_CACHE["ts"]) > _QUEUE_CACHE_TTL:
+        _QUEUE_CACHE["data"] = await asyncio.to_thread(_read_queues_sync)
+        _QUEUE_CACHE["ts"] = now
+    return _QUEUE_CACHE["data"]
+
+
@system_activity_bp.route("/queues", methods=["GET"])
 async def get_queues():
    """Per-queue Redis LLEN. Cached 2s.

    Response: {queues: {name: depth_or_null}, fetched_at: iso8601}
    """
-    now = time.time()
-    if _QUEUE_CACHE["data"] is None or (now - _QUEUE_CACHE["ts"]) > _QUEUE_CACHE_TTL:
-        _QUEUE_CACHE["data"] = await asyncio.to_thread(_read_queues_sync)
-        _QUEUE_CACHE["ts"] = now
-    return jsonify(_QUEUE_CACHE["data"])
+    return jsonify(await _queues_cached())


@system_activity_bp.route("/workers", methods=["GET"])
@@ -107,6 +113,35 @@ async def get_workers():
    return jsonify(_WORKER_CACHE["data"])


+@system_activity_bp.route("/summary", methods=["GET"])
+async def get_summary():
+    """One-call rollup for the always-on TopNav pipeline indicator:
+    scheduler health, per-queue pending depths, currently-running count, and
+    recent (24h) failure count. Cheap — cached queue LLENs + two TaskRun
+    counts — so it's safe to poll app-wide."""
+    queues_data = await _queues_cached()
+    depths = queues_data.get("queues", {})
+    queued_total = sum(v for v in depths.values() if isinstance(v, int))
+    since = datetime.now(UTC) - timedelta(hours=24)
+    async with get_session() as session:
+        scheduler = await scheduler_status(session)
+        running = (await session.execute(
+            select(func.count(TaskRun.id)).where(TaskRun.status == "running")
+        )).scalar_one()
+        failing = (await session.execute(
+            select(func.count(TaskRun.id))
+            .where(TaskRun.status.in_(["error", "timeout"]))
+            .where(TaskRun.finished_at >= since)
+        )).scalar_one()
+    return jsonify({
+        "scheduler": scheduler,
+        "queues": depths,
+        "queued_total": queued_total,
+        "running": int(running),
+        "failing": int(failing),
+    })
+
+
@system_activity_bp.route("/runs", methods=["GET"])
 async def list_runs():
    """Paginated task_run history. Query params:
@@ -14,6 +14,7 @@ from sqlalchemy import desc, select

 from ..extensions import get_session
 from ..models import BackupRun, ImportSettings
+from ._responses import error_response as _bad

 system_backup_bp = Blueprint(
    "system_backup", __name__, url_prefix="/api/system/backup",
@@ -29,12 +30,6 @@ _BACKUP_SETTINGS_FIELDS = (
 )


-def _bad(error: str, *, status: int = 400, **extra):
-    body = {"error": error}
-    body.update(extra)
-    return jsonify(body), status
-
-
 def _row_to_dict(r: BackupRun) -> dict:
    return {
        "id": r.id,
@@ -232,9 +227,7 @@ async def delete_run(run_id: int):
@system_backup_bp.route("/settings", methods=["GET"])
 async def get_settings():
    async with get_session() as session:
-        row = (await session.execute(
-            select(ImportSettings).where(ImportSettings.id == 1)
-        )).scalar_one()
+        row = await ImportSettings.load(session)
    return jsonify({
        "backup_db_nightly_enabled": row.backup_db_nightly_enabled,
        "backup_db_nightly_hour_utc": row.backup_db_nightly_hour_utc,
@@ -254,9 +247,7 @@ async def patch_settings():
        return err

    async with get_session() as session:
-        row = (await session.execute(
-            select(ImportSettings).where(ImportSettings.id == 1)
-        )).scalar_one()
+        row = await ImportSettings.load(session)
        for field in _BACKUP_SETTINGS_FIELDS:
            if field in body:
                setattr(row, field, body[field])
@@ -15,6 +15,7 @@ from ..services.tag_service import (
    TagService,
    TagValidationError,
 )
+from ..utils.tag_prefix import parse_kind_prefix

 tags_bp = Blueprint("tags", __name__, url_prefix="/api")

@@ -105,13 +106,39 @@ async def directory():

@tags_bp.route("/tags", methods=["POST"])
 async def create_tag():
+    """Create a tag. Two input shapes accepted:
+      1. Explicit: {name, kind, fandom_id?} — caller already split, kind wins.
+      2. IR-suffix: {name} where name = "kind:Name" (e.g. "artist:Eric").
+         The server runs parse_kind_prefix(name) to derive kind; the colon
+         and prefix are stripped from the stored tag name. If no recognized
+         prefix is present, the kind defaults to `general`.
+    Explicit kind ALWAYS wins (backward-compat for existing callers).
+    """
    body = await request.get_json()
-    if not body or "name" not in body or "kind" not in body:
-        return jsonify({"error": "name and kind required"}), 400
+    if not body or "name" not in body:
+        return jsonify({"error": "name required"}), 400
    name = body["name"]
-    kind = _coerce_kind(body["kind"])
-    if kind is None:
-        return jsonify({"error": f"invalid kind {body['kind']!r}"}), 400
+    explicit_kind_raw = body.get("kind")
+
+    if explicit_kind_raw is not None:
+        # Caller provided kind — honor it; don't re-parse.
+        kind = _coerce_kind(explicit_kind_raw)
+        if kind is None:
+            return jsonify({"error": f"invalid kind {explicit_kind_raw!r}"}), 400
+    else:
+        # IR-style: parse "kind:Name" from the raw name.
+        parsed_kind, parsed_name = parse_kind_prefix(name)
+        if parsed_kind is not None:
+            name = parsed_name
+            kind = _coerce_kind(parsed_kind)
+            # parse_kind_prefix only returns kinds from KNOWN_KINDS which
+            # are all valid TagKind members, so _coerce_kind can't return
+            # None here — but defensive.
+            if kind is None:
+                return jsonify({"error": f"invalid kind {parsed_kind!r}"}), 400
+        else:
+            kind = TagKind.general
+
    fandom_id = body.get("fandom_id")

    async with get_session() as session:
@@ -218,6 +245,12 @@ async def merge_tag(source_id: int):
        from ..tasks.ml import apply_allowlist_tags

        apply_allowlist_tags.delay(tag_id=result.target_id)
+    # Tag merge invalidates the target's centroid (the merged-in source
+    # tag's images now contribute to it). Daily list_drifted catches it
+    # within 24h, but eager recompute closes the suggestion-quality dip
+    # in the meantime. Audit 2026-06-02.
+    from ..tasks.ml import recompute_centroid
+    recompute_centroid.delay(result.target_id)
    return jsonify(
        {
            "target": {
@@ -1,5 +1,7 @@
 """Thumbnail admin API: backfill trigger."""

+import asyncio
+
 from quart import Blueprint, jsonify

 thumbnails_bp = Blueprint("thumbnails", __name__, url_prefix="/api/thumbnails")
@@ -7,7 +9,20 @@ thumbnails_bp = Blueprint("thumbnails", __name__, url_prefix="/api/thumbnails")

@thumbnails_bp.route("/backfill", methods=["POST"])
 async def trigger_backfill():
-    from ..tasks.thumbnail import backfill_thumbnails
+    """Run the backfill scan synchronously, return the counts. The actual
+    thumbnail generation work is still off-loaded to the thumbnail Celery
+    queue via `generate_thumbnail.delay()` per missing row — so this
+    handler is fast even on a 100k-image library (a scan is just SELECT
+    id, thumbnail_path + a file.stat() per row, no heavy work).

-    r = backfill_thumbnails.delay()
-    return jsonify({"celery_task_id": r.id}), 202
+    Operator-flagged 2026-06-01: the previous fire-and-forget shape
+    returned `{celery_task_id}` only, so the admin UI had no idea whether
+    backfill found 0 or 5000 candidates — \"found nothing\" was
+    indistinguishable from \"the worker isn't picking up the task.\""""
+    from ..tasks.thumbnail import _run_backfill_scan
+
+    # Sync scan inside an executor so we don't block the event loop.
+    counts = await asyncio.get_running_loop().run_in_executor(
+        None, _run_backfill_scan,
+    )
+    return jsonify(counts), 200
@@ -28,7 +28,6 @@ def make_celery() -> Celery:
            "backend.app.tasks.import_file",
            "backend.app.tasks.thumbnail",
            "backend.app.tasks.maintenance",
-            "backend.app.tasks.migration",
            "backend.app.tasks.ml",
            "backend.app.tasks.download",
            "backend.app.tasks.backup",
@@ -45,7 +44,6 @@ def make_celery() -> Celery:
            "backend.app.tasks.download.*": {"queue": "download"},
            "backend.app.tasks.scan.*": {"queue": "scan"},
            "backend.app.tasks.maintenance.*": {"queue": "maintenance"},
-            "backend.app.tasks.migration.*": {"queue": "maintenance"},
            "backend.app.tasks.backup.*": {"queue": "maintenance"},
            "backend.app.tasks.admin.*": {"queue": "maintenance"},
            "backend.app.tasks.library_audit.*": {"queue": "maintenance"},
@@ -87,6 +85,10 @@ def make_celery() -> Celery:
                "task": "backend.app.tasks.maintenance.cleanup_old_download_events",
                "schedule": 86400.0,  # daily
            },
+            "recover-stalled-download-events": {
+                "task": "backend.app.tasks.maintenance.recover_stalled_download_events",
+                "schedule": 300.0,  # every 5 min, matches recover-interrupted-tasks
+            },
            "recover-stalled-task-runs": {
                "task": "backend.app.tasks.maintenance.recover_stalled_task_runs",
                "schedule": 300.0,  # every 5 min, matches recover-interrupted-tasks
@@ -103,6 +105,41 @@ def make_celery() -> Celery:
                "task": "backend.app.tasks.backup.prune_backups",
                "schedule": 86400.0,  # daily
            },
+            # Audit 2026-06-02 — three new per-entity recovery sweeps.
+            # Each runs every 5 min like the other recover_stalled_*
+            # sweeps; each is a no-op when nothing is stuck.
+            "recover-stalled-backup-runs": {
+                "task": "backend.app.tasks.maintenance.recover_stalled_backup_runs",
+                "schedule": 300.0,
+            },
+            "recover-stalled-library-audit-runs": {
+                "task": "backend.app.tasks.maintenance.recover_stalled_library_audit_runs",
+                "schedule": 300.0,
+            },
+            "recover-stalled-import-batches": {
+                "task": "backend.app.tasks.maintenance.recover_stalled_import_batches",
+                "schedule": 300.0,
+            },
+            # Audit 2026-06-02 — daily retention for two entities
+            # whose terminal rows otherwise accumulate forever.
+            "prune-library-audit-runs": {
+                "task": "backend.app.tasks.maintenance.prune_library_audit_runs",
+                "schedule": 86400.0,
+            },
+            "prune-import-batches": {
+                "task": "backend.app.tasks.maintenance.prune_import_batches",
+                "schedule": 86400.0,
+            },
+            # Audit 2026-06-02 — backfill_thumbnails's docstring claimed
+            # "periodic Beat" but the entry was never registered, so the
+            # library got no self-healing thumbnail repair; only the
+            # manual admin-UI button fired it. Daily cadence is gentle
+            # (the task is idempotent and only enqueues regen for rows
+            # whose stored thumbnails are missing or corrupt).
+            "backfill-thumbnails-daily": {
+                "task": "backend.app.tasks.thumbnail.backfill_thumbnails",
+                "schedule": 86400.0,
+            },
        },
        timezone="UTC",
    )
@@ -54,7 +54,14 @@ _INT32_MIN = -2_147_483_648

 def _queue_for(task) -> str:
    """Reverse the task→queue routing from celery_app.task_routes.
-    Keep in sync if task_routes is reordered."""
+    Keep in sync if task_routes is reordered.
+
+    Audit 2026-06-02: backup/admin/library_audit prefixes were
+    missing here even though task_routes sent all three to
+    'maintenance'. The TaskRun.queue column then lied for those
+    rows (claimed 'default') so per-queue dashboard filters and
+    per-queue threshold overrides silently missed them.
+    """
    name = getattr(task, "name", "") or ""
    if name.startswith("backend.app.tasks.import_file."):
        return "import"
@@ -68,7 +75,9 @@ def _queue_for(task) -> str:
        return "scan"
    if name.startswith((
        "backend.app.tasks.maintenance.",
-        "backend.app.tasks.migration.",
+        "backend.app.tasks.backup.",
+        "backend.app.tasks.admin.",
+        "backend.app.tasks.library_audit.",
    )):
        return "maintenance"
    return "default"
@@ -12,7 +12,6 @@ from .import_batch import ImportBatch
 from .import_settings import ImportSettings
 from .import_task import ImportTask
 from .library_audit_run import LibraryAuditRun
-from .migration_run import MigrationRun
 from .ml_settings import MLSettings
 from .post import Post
 from .post_attachment import PostAttachment
@@ -46,7 +45,6 @@ __all__ = [
    "ImportSettings",
    "LibraryAuditRun",
    "MLSettings",
-    "MigrationRun",
    "TagAlias",
    "TagAllowlist",
    "TagReferenceEmbedding",
@@ -34,8 +34,12 @@ class ImageProvenance(Base):
    post_id: Mapped[int] = mapped_column(
        ForeignKey("post.id", ondelete="CASCADE"), nullable=False, index=True
    )
-    source_id: Mapped[int] = mapped_column(
-        ForeignKey("source.id", ondelete="CASCADE"), nullable=False, index=True
+    # Nullable since alembic 0030 — provenance rows for filesystem-imported
+    # content with no subscription have NULL source_id. FK ondelete SET
+    # NULL so deleting a Source detaches its provenance rows instead of
+    # destroying the linkage between image and post.
+    source_id: Mapped[int | None] = mapped_column(
+        ForeignKey("source.id", ondelete="SET NULL"), nullable=True, index=True
    )
    captured_metadata: Mapped[dict | None] = mapped_column(JSON, nullable=True)
    captured_at: Mapped[datetime] = mapped_column(
@@ -4,7 +4,7 @@ Enforced as a single row via a CHECK (id = 1) constraint. The application
 always SELECTs id=1 and never inserts/deletes after the initial migration.
 """

-from sqlalchemy import Boolean, CheckConstraint, Float, Integer, Text
+from sqlalchemy import Boolean, CheckConstraint, Float, Integer, Text, select
 from sqlalchemy.orm import Mapped, mapped_column

 from .base import Base
@@ -63,3 +63,13 @@ class ImportSettings(Base):
    backup_images_keep_last_n: Mapped[int] = mapped_column(
        Integer, nullable=False, default=3,
    )
+
+    @classmethod
+    async def load(cls, session) -> ImportSettings:
+        """The singleton settings row (id=1), via an async session."""
+        return (await session.execute(select(cls).where(cls.id == 1))).scalar_one()
+
+    @classmethod
+    def load_sync(cls, session) -> ImportSettings:
+        """The singleton settings row (id=1), via a sync session."""
+        return session.execute(select(cls).where(cls.id == 1)).scalar_one()
@@ -8,7 +8,16 @@ been processing longer than the stuck-task threshold.

 from datetime import datetime

-from sqlalchemy import BigInteger, DateTime, ForeignKey, Integer, String, Text, func
+from sqlalchemy import (
+    BigInteger,
+    Boolean,
+    DateTime,
+    ForeignKey,
+    Integer,
+    String,
+    Text,
+    func,
+)
 from sqlalchemy.orm import Mapped, mapped_column, relationship

 from .base import Base
@@ -26,6 +35,13 @@ class ImportTask(Base):
    task_type: Mapped[str] = mapped_column(String(16), nullable=False)  # media|archive
    status: Mapped[str] = mapped_column(String(16), nullable=False, default="pending", index=True)

+    # Poison-pill circuit breaker (alembic 0026). recovery_count tracks
+    # how many times the stuck-task sweep has re-queued this row; after
+    # the cap it's failed with a diagnostic instead of looping. refetched
+    # bounds the one-shot re-download remediation to a single attempt.
+    recovery_count: Mapped[int] = mapped_column(Integer, nullable=False, default=0)
+    refetched: Mapped[bool] = mapped_column(Boolean, nullable=False, default=False)
+
    result_image_id: Mapped[int | None] = mapped_column(
        ForeignKey("image_record.id", ondelete="SET NULL"), nullable=True
    )
@@ -1,37 +0,0 @@
-"""MigrationRun — tracks each FC-5 migration invocation (backup/gs/ir/etc).
-
-kind/status are String(32) not Postgres ENUM so adding kinds later
-doesn't need a schema migration. The API layer validates values.
-"""
-
-from datetime import datetime
-
-import sqlalchemy as sa
-from sqlalchemy import Boolean, DateTime, Integer, String, Text, func
-from sqlalchemy.dialects.postgresql import JSONB
-from sqlalchemy.orm import Mapped, mapped_column
-
-from .base import Base
-
-
-class MigrationRun(Base):
-    __tablename__ = "migration_run"
-
-    id: Mapped[int] = mapped_column(Integer, primary_key=True)
-    kind: Mapped[str] = mapped_column(String(32), nullable=False, index=True)
-    status: Mapped[str] = mapped_column(String(32), nullable=False, index=True)
-    dry_run: Mapped[bool] = mapped_column(Boolean, nullable=False, default=False)
-    started_at: Mapped[datetime] = mapped_column(
-        DateTime(timezone=True), nullable=False, server_default=func.now(),
-    )
-    finished_at: Mapped[datetime | None] = mapped_column(
-        DateTime(timezone=True), nullable=True,
-    )
-    counts: Mapped[dict] = mapped_column(
-        JSONB, nullable=False, default=dict, server_default=sa.text("'{}'::jsonb"),
-    )
-    error: Mapped[str | None] = mapped_column(Text, nullable=True)
-    metadata_: Mapped[dict] = mapped_column(
-        "metadata", JSONB, nullable=False, default=dict,
-        server_default=sa.text("'{}'::jsonb"),
-    )
@@ -15,17 +15,15 @@ class MLSettings(Base):
    __table_args__ = (CheckConstraint("id = 1", name="singleton"),)

    id: Mapped[int] = mapped_column(Integer, primary_key=True)
-    suggestion_threshold_artist: Mapped[float] = mapped_column(
-        Float, nullable=False, default=0.30
-    )
    suggestion_threshold_character: Mapped[float] = mapped_column(
-        Float, nullable=False, default=0.50
-    )
-    suggestion_threshold_copyright: Mapped[float] = mapped_column(
-        Float, nullable=False, default=0.50
+        Float, nullable=False, default=0.70
    )
+    # Default raised 0.50 → 0.70 on 2026-06-02 — operator-flagged 0.50
+    # surfaced too many low-confidence picks; 0.70 keeps the rail
+    # signal-rich while still surfacing more than the original 0.95
+    # which hid almost everything. Operator-tunable via Settings → ML.
    suggestion_threshold_general: Mapped[float] = mapped_column(
-        Float, nullable=False, default=0.95
+        Float, nullable=False, default=0.70
    )
    centroid_similarity_threshold: Mapped[float] = mapped_column(
        Float, nullable=False, default=0.55
@@ -1,6 +1,9 @@
-"""Post — provenance anchor for content downloaded from a Source.
+"""Post — provenance anchor for one creator post (may contain many images).

-A Post is one creator post; it may contain many images/videos.
+`source_id` is nullable since alembic 0030 — filesystem-imported posts
+with no live subscription have NULL source_id. `artist_id` is the
+denormalized always-present link to the creator (added in 0030 so
+artist-filter queries don't depend on the Source detour).
 """

 from datetime import datetime
@@ -14,12 +17,25 @@ from .base import Base
 class Post(Base):
    __tablename__ = "post"
    __table_args__ = (
+        # Source-bound dedup. Postgres treats NULL != NULL so rows
+        # with source_id IS NULL aren't deduped by this constraint;
+        # the partial unique index `uq_post_artist_external_id_null_source`
+        # (created in alembic 0030) covers that case via
+        # (artist_id, external_post_id).
        UniqueConstraint("source_id", "external_post_id", name="uq_post_source_external_id"),
    )

    id: Mapped[int] = mapped_column(Integer, primary_key=True)
-    source_id: Mapped[int] = mapped_column(
-        ForeignKey("source.id", ondelete="CASCADE"), nullable=False, index=True
+    source_id: Mapped[int | None] = mapped_column(
+        ForeignKey("source.id", ondelete="SET NULL"), nullable=True, index=True
+    )
+    # Denormalized; always equals source.artist_id when source_id is set
+    # (the importer is responsible for keeping them consistent on insert).
+    # Filter queries (artist detail, artist-scoped posts feed) use this
+    # directly instead of joining through Source.
+    artist_id: Mapped[int] = mapped_column(
+        ForeignKey("artist.id", ondelete="CASCADE"),
+        nullable=False, index=True,
    )
    external_post_id: Mapped[str] = mapped_column(String(128), nullable=False)
    post_url: Mapped[str | None] = mapped_column(Text, nullable=True)
@@ -26,7 +26,21 @@ class Source(Base):

    last_checked_at: Mapped[datetime | None] = mapped_column(DateTime(timezone=True), nullable=True)
    last_error: Mapped[str | None] = mapped_column(Text, nullable=True)
+    # alembic 0032: last ErrorType category (auth_error, rate_limited,
+    # not_found, ...). Lets FailingSourcesCard surface the taxonomy as
+    # a colored chip so operators can bulk-triage by error class. Set
+    # by _update_source_health alongside last_error; cleared on 'ok'.
+    error_type: Mapped[str | None] = mapped_column(String(32), nullable=True, index=True)
    check_interval_override: Mapped[int | None] = mapped_column(Integer, nullable=True)
    consecutive_failures: Mapped[int] = mapped_column(Integer, nullable=False, default=0)

+    # alembic 0031: sticky deep-scan budget. When > 0, the next N download
+    # runs use gallery-dl's full-walk config (skip: True + 1800s timeout);
+    # when 0, runs use tick mode (skip: "exit:20" + 870s, exits early once
+    # 20 contiguous archived items are seen). Auto-decrements per run, with
+    # an auto-reset to 0 on clean exit + zero downloads (queue drained).
+    backfill_runs_remaining: Mapped[int] = mapped_column(
+        Integer, nullable=False, default=0, server_default="0",
+    )
+
    artist = relationship("Artist", back_populates="sources")
@@ -35,8 +35,10 @@ class TagKind(StrEnum):
    series = "series"
    archive = "archive"
    post = "post"
-    meta = "meta"
-    rating = "rating"
+    # `meta` and `rating` retired by operator 2026-05-26 (alembic 0023).
+    # `artist` retired in FC-2d-vii-c — artists are first-class entities
+    # via Artist/Source rows now, not tags — but the enum value stays
+    # to keep historic tag rows queryable.


 image_tag = Table(
@@ -127,17 +127,20 @@ class ArtistDirectoryService:
                ImageRecord.artist_id.label("artist_id"),
                ImageRecord.sha256.label("sha256"),
                ImageRecord.mime.label("mime"),
+                ImageRecord.thumbnail_path.label("thumbnail_path"),
                rn,
            )
            .where(ImageRecord.artist_id.in_(artist_ids))
            .subquery()
        )
        stmt = (
-            select(sub.c.artist_id, sub.c.sha256, sub.c.mime)
+            select(
+                sub.c.artist_id, sub.c.sha256, sub.c.mime, sub.c.thumbnail_path,
+            )
            .where(sub.c.rn <= _PREVIEW_COUNT)
            .order_by(sub.c.artist_id, sub.c.rn)
        )
        out: dict[int, list[str]] = {}
-        for aid, sha, mime in (await self.session.execute(stmt)).all():
-            out.setdefault(aid, []).append(thumbnail_url(sha, mime))
+        for aid, sha, mime, tp in (await self.session.execute(stmt)).all():
+            out.setdefault(aid, []).append(thumbnail_url(tp, sha, mime))
        return out
@@ -58,13 +58,17 @@ class ArtistService:
            )
        ).scalar_one()

+        # Posts under this artist that have at least one image attached.
+        # Use Post.artist_id (alembic 0030) for the artist filter; keep
+        # the ImageProvenance JOIN so date bounds reflect only image-
+        # bearing posts (matches the original semantic). NULL-source
+        # posts now surface too.
        date_row = (
            await self.session.execute(
                select(func.min(Post.post_date), func.max(Post.post_date))
                .select_from(Post)
                .join(ImageProvenance, ImageProvenance.post_id == Post.id)
-                .join(Source, Source.id == ImageProvenance.source_id)
-                .where(Source.artist_id == aid)
+                .where(Post.artist_id == aid)
            )
        ).first()
        dmin, dmax = date_row if date_row else (None, None)
@@ -98,14 +102,14 @@ class ArtistService:
            )
        ).all()

+        # Same Post.artist_id direct filter — counts NULL-source posts too.
        month = func.date_trunc("month", Post.post_date).label("m")
        activity = (
            await self.session.execute(
                select(month, func.count(func.distinct(ImageProvenance.image_record_id)))
                .select_from(Post)
                .join(ImageProvenance, ImageProvenance.post_id == Post.id)
-                .join(Source, Source.id == ImageProvenance.source_id)
-                .where(and_(Source.artist_id == aid, Post.post_date.isnot(None)))
+                .where(and_(Post.artist_id == aid, Post.post_date.isnot(None)))
                .group_by(month)
                .order_by(month)
            )
@@ -114,9 +118,7 @@ class ArtistService:
        post_count = (
            await self.session.execute(
                select(func.count(func.distinct(Post.id)))
-                .select_from(Post)
-                .join(Source, Source.id == Post.source_id)
-                .where(Source.artist_id == aid)
+                .where(Post.artist_id == aid)
            )
        ).scalar_one()

@@ -198,7 +200,7 @@ class ArtistService:
                    "mime": r.mime,
                    "width": r.width,
                    "height": r.height,
-                    "thumbnail_url": thumbnail_url(r.sha256, r.mime),
+                    "thumbnail_url": thumbnail_url(r.thumbnail_path, r.sha256, r.mime),
                }
                for r in rows
            ],
@@ -206,27 +208,32 @@ class ArtistService:
        )

    async def find_or_create(self, name: str) -> tuple[Artist, bool]:
-        """Return (artist, created). Slug-keyed; idempotent under races."""
+        """Return (artist, created). Slug-keyed; idempotent under races.
+
+        Audit 2026-06-02: switched from session.rollback() to a
+        begin_nested savepoint + IntegrityError recovery so a lost
+        race doesn't unwind the calling request's surrounding work.
+        Mirrors importer._get_or_create.
+        """
        cleaned = (name or "").strip()
        if not cleaned:
            raise ValueError("artist name must not be empty")
        slug = slugify(cleaned)

-        existing = (await self.session.execute(
-            select(Artist).where(Artist.slug == slug)
-        )).scalar_one_or_none()
+        select_existing = select(Artist).where(Artist.slug == slug)
+        existing = (await self.session.execute(select_existing)).scalar_one_or_none()
        if existing is not None:
            return existing, False

-        artist = Artist(name=cleaned, slug=slug)
-        self.session.add(artist)
+        sp = await self.session.begin_nested()
        try:
+            artist = Artist(name=cleaned, slug=slug)
+            self.session.add(artist)
            await self.session.flush()
+            await sp.commit()
        except IntegrityError:
-            await self.session.rollback()
-            existing = (await self.session.execute(
-                select(Artist).where(Artist.slug == slug)
-            )).scalar_one()
+            await sp.rollback()
+            existing = (await self.session.execute(select_existing)).scalar_one()
            return existing, False
        await self.session.commit()
        return artist, True
@@ -6,17 +6,16 @@ HTTP handlers (small ops) and from Celery tasks in
 backend.app.tasks.admin (long ops).

 This module is the PERMANENT home of artist-cascade + image-unlink
-logic. The legacy copy at backend/app/services/migrators/cleanup.py
-stays in place until FC-3j; FC-3j will replace its body with thin
-re-exports from this module and then delete the wrapper.
+logic. (The legacy migrators/cleanup.py copy was removed with the rest of
+the one-and-done GS/IR migration tooling.)
 """
 from __future__ import annotations

-from datetime import UTC, datetime
+from datetime import UTC, datetime, timedelta
 from pathlib import Path
 from typing import Any

-from sqlalchemy import func, select, update
+from sqlalchemy import func, or_, select, update
 from sqlalchemy.orm import Session

 from ..models import Artist, ImageRecord, LibraryAuditRun, Tag
@@ -188,10 +187,14 @@ def unlink_image_files(
            out["thumbnail"] = True
        except OSError:
            out["thumbnail"] = False
-    # Convention thumbs dir — try all extensions; missing OK.
+    # Convention thumbs dir — try both extensions thumbnailer writes
+    # (.jpg for opaque, .png for alpha). `.webp` used to be in this
+    # tuple but the thumbnailer never writes it (operator-flagged in
+    # the 2026-06-02 audit) — keep the tuple aligned with what
+    # actually lands on disk.
    if image.sha256:
        bucket = image.sha256[:3]
-        for ext in ("jpg", "png", "webp"):
+        for ext in ("jpg", "png"):
            try:
                (images_root / "thumbs" / bucket / f"{image.sha256}.{ext}").unlink(
                    missing_ok=True,
@@ -355,18 +358,101 @@ def prune_unused_tags(session: Session, *, dry_run: bool = False) -> dict:
    Returns:
      dry_run=True:  {"count": N, "sample_names": [first 50]}
      dry_run=False: {"deleted": N, "sample_names": [first 50]}
+
+    Implementation note: the previous SELECT-ids → DELETE-WHERE-IN
+    pattern was vulnerable to the psycopg 65535-parameter ceiling on
+    libraries with tag explosions. The live delete now runs a single
+    DELETE with the same NOT-IN predicate find_unused_tags uses, so
+    the row count scales without binding every id as a parameter.
+    Audit 2026-06-02.
    """
-    unused = find_unused_tags(session)
-    sample = [t.name for t in unused[:50]]
+    sample_rows = find_unused_tags(session, limit=50)
+    sample = [t.name for t in sample_rows]
+    used_via_image_tag = select(image_tag.c.tag_id).distinct()
+    used_via_series = select(SeriesPage.series_tag_id).where(
+        SeriesPage.series_tag_id.is_not(None)
+    ).distinct()
    if dry_run:
-        return {"count": len(unused), "sample_names": sample}
-    ids = [t.id for t in unused]
-    if ids:
-        session.execute(
-            Tag.__table__.delete().where(Tag.id.in_(ids))
+        count = session.execute(
+            select(func.count())
+            .select_from(Tag)
+            .where(Tag.id.not_in(used_via_image_tag))
+            .where(Tag.id.not_in(used_via_series))
+        ).scalar_one()
+        return {"count": count, "sample_names": sample}
+    result = session.execute(
+        Tag.__table__.delete()
+        .where(Tag.id.not_in(used_via_image_tag))
+        .where(Tag.id.not_in(used_via_series))
+    )
+    session.commit()
+    return {"deleted": result.rowcount or 0, "sample_names": sample}
+
+
+# Legacy tags FC no longer uses, in two shapes:
+#   (1) kinds the tag input never produces — archive/post/artist.
+#       provenance (post grouping) + archive membership are their own
+#       systems now, and artists are first-class Artist/Source rows.
+#       meta/rating were already hard-deleted by alembic 0023.
+#   (2) name prefixes from IR kinds FC never adopted — `source:*`.
+#       ImageRepo had a `source` kind; FC's enum doesn't, so ir_ingest
+#       fell those back to `general` (kind=general, name="source:patreon"
+#       etc.). They can't be caught by kind, so we match the name prefix.
+PURGEABLE_TAG_KINDS = ("archive", "post", "artist")
+LEGACY_NAME_PREFIXES = ("source:",)
+
+
+def _legacy_tag_predicate():
+    name_clauses = [Tag.name.like(f"{p}%") for p in LEGACY_NAME_PREFIXES]
+    return or_(Tag.kind.in_(PURGEABLE_TAG_KINDS), *name_clauses)
+
+
+def purge_legacy_tags(session: Session, *, dry_run: bool = False) -> dict:
+    """Count (dry_run) or delete legacy IR-migration tags: archive/post/
+    artist-kind tags PLUS general tags whose name matches a legacy
+    prefix (source:*).
+
+    CASCADE on image_tag / tag_alias / tag_allowlist /
+    tag_reference_embedding / tag_suggestion_rejection / series_page
+    clears the related rows on the parent DELETE.
+
+    Returns:
+      {"by_kind": {kind: count, ...},        # kind-matched rows
+       "by_prefix": {"source:*": count},     # name-prefix-matched rows
+       "count": total, "sample_names": [first 50],
+       and on live runs "deleted": total}
+    """
+    predicate = _legacy_tag_predicate()
+    rows = session.execute(
+        select(Tag.id, Tag.name, Tag.kind).where(predicate)
+    ).all()
+    by_kind: dict[str, int] = {}
+    by_prefix: dict[str, int] = {}
+    for _id, name, kind in rows:
+        # Classify by name-prefix first so a source:* row counts once,
+        # under the prefix bucket, regardless of its (general) kind.
+        matched_prefix = next(
+            (p for p in LEGACY_NAME_PREFIXES if name.startswith(p)), None,
        )
+        if matched_prefix is not None:
+            label = f"{matched_prefix}*"
+            by_prefix[label] = by_prefix.get(label, 0) + 1
+        else:
+            key = kind.value if hasattr(kind, "value") else str(kind)
+            by_kind[key] = by_kind.get(key, 0) + 1
+    sample = [name for _id, name, _kind in rows[:50]]
+    total = len(rows)
+    result = {
+        "by_kind": by_kind, "by_prefix": by_prefix,
+        "count": total, "sample_names": sample,
+    }
+    if dry_run:
+        return result
+    if total:
+        session.execute(Tag.__table__.delete().where(predicate))
        session.commit()
-    return {"deleted": len(ids), "sample_names": sample}
+    result["deleted"] = total
+    return result


 # ---------------------------------------------------------------------------
@@ -435,6 +521,9 @@ class ConfirmTokenMismatch(Exception):
 _VALID_RULES = ("transparency", "single_color")


+_AUDIT_GUARD_THRESHOLD_MINUTES = 135  # matches LIBRARY_AUDIT_STALL_THRESHOLD_MINUTES
+
+
 def start_audit_run(
    session: Session, *, rule: str, params: dict[str, Any],
 ) -> int:
@@ -442,11 +531,21 @@ def start_audit_run(
    scan_library_for_rule Celery task. Returns the new audit_id.

    Concurrent-runs guard: raises AuditAlreadyRunning if any audit_run
-    has status='running'. Operator must cancel or wait."""
+    has status='running' AND started recently. Audit 2026-06-02 made
+    the guard age-aware: a SIGKILL'd run leaves a row in 'running'
+    that the recovery sweep flips on its next pass (~5 min), but a
+    fresh start_audit_run between the SIGKILL and the sweep would
+    previously block forever. Past the threshold, treat the running
+    row as stale and let the sweep clean it up — the new run still
+    gets to start.
+    """
    if rule not in _VALID_RULES:
        raise ValueError(f"unknown rule {rule!r}; expected one of {_VALID_RULES}")
+    cutoff = datetime.now(UTC) - timedelta(minutes=_AUDIT_GUARD_THRESHOLD_MINUTES)
    existing = session.execute(
-        select(LibraryAuditRun.id).where(LibraryAuditRun.status == "running")
+        select(LibraryAuditRun.id)
+        .where(LibraryAuditRun.status == "running")
+        .where(LibraryAuditRun.started_at >= cutoff)
    ).scalar_one_or_none()
    if existing is not None:
        raise AuditAlreadyRunning(existing)
@@ -1,40 +1,82 @@
 """Fernet-based encryption for credential blobs.

 The key is a single 32-byte value (urlsafe-base64-encoded; what
-Fernet.generate_key produces) stored at a fixed path inside the
-images/data root. Created on first boot if absent; mode 0600. No KDF
-needed — the file contents are already maximum-entropy random bytes.
+Fernet.generate_key produces) stored at /images/secrets/credential_key.b64
+(mode 0600, parent dir 0700). The 2026-06-02 audit caught a silent
+key-regeneration path: on a partial disaster restore where the DB was
+restored but the secrets dir was lost, the old `_load_or_create_key`
+would mint a fresh key with no log, producing a working-looking system
+where every authenticated download failed AUTH_ERROR until the operator
+re-uploaded every credential by hand. Now the constructor refuses to
+auto-generate unless either:

-Operator backup procedure must include this file alongside the rest
-of /images/ — losing it makes existing encrypted_blob rows
-undecryptable (recovery = delete the rows and re-upload).
+  * the caller explicitly passes `bootstrap_ok=True` (tests, scripts), or
+  * the env var `CURATOR_BOOTSTRAP_NEW_KEY=1` is set (operator opt-in
+    during first-time setup).
+
+Otherwise it raises `MissingCredentialKey` so the app fails fast at
+startup and the operator can restore the key file from backup.
+
+Operator backup procedure must include /images/secrets/ alongside the
+rest of /images/ — losing the key file makes existing encrypted_blob
+rows undecryptable (recovery = delete the rows and re-upload).
 """

+import logging
 import os
 from pathlib import Path

 from cryptography.fernet import Fernet, InvalidToken

+log = logging.getLogger(__name__)
+
+_BOOTSTRAP_ENV_VAR = "CURATOR_BOOTSTRAP_NEW_KEY"
+

 class InvalidCredentialBlob(Exception):
    """Raised when decryption fails (wrong key, tampered blob, …)."""


+class MissingCredentialKey(Exception):
+    """The Fernet key file is missing AND the caller hasn't opted in to
+    generating a new one. Audit 2026-06-02: prevents silent key
+    regeneration on partial DB-restored / secrets-lost deployments.
+    Set CURATOR_BOOTSTRAP_NEW_KEY=1 for first-time setup, or restore the
+    key file from backup."""
+
+
 class CredentialCrypto:
    """Fernet encrypt/decrypt with an on-disk key file.

-    Instantiate with a path; the file is created on first access and
-    reused thereafter. Tests pass a tmp_path; production calls with
+    Instantiate with a path; the file is loaded if present, or created
+    if absent AND the caller has opted in (bootstrap_ok=True or
+    CURATOR_BOOTSTRAP_NEW_KEY=1 env var). Production sites:
    `IMAGES_ROOT / "secrets" / "credential_key.b64"`.
    """

-    def __init__(self, key_path: Path):
+    def __init__(self, key_path: Path, *, bootstrap_ok: bool | None = None):
        self._key_path = Path(key_path)
-        self._fernet = Fernet(self._load_or_create_key())
+        if bootstrap_ok is None:
+            bootstrap_ok = os.environ.get(_BOOTSTRAP_ENV_VAR) == "1"
+        self._fernet = Fernet(self._load_or_create_key(bootstrap_ok))

-    def _load_or_create_key(self) -> bytes:
+    def _load_or_create_key(self, bootstrap_ok: bool) -> bytes:
        if self._key_path.exists():
            return self._key_path.read_bytes()
+        if not bootstrap_ok:
+            raise MissingCredentialKey(
+                f"Fernet key file not found at {self._key_path}. "
+                f"For first-time setup, set {_BOOTSTRAP_ENV_VAR}=1. "
+                f"If this is a restored instance, restore the key file "
+                f"from backup — generating a new one would make every "
+                f"existing Credential row undecryptable."
+            )
+        log.warning(
+            "Generating NEW Fernet credential key at %s. Any existing "
+            "encrypted_blob rows in the DB will be undecryptable — "
+            "re-upload each credential after this completes.",
+            self._key_path,
+        )
        parent = self._key_path.parent
        parent.mkdir(parents=True, exist_ok=True)
        os.chmod(parent, 0o700)
@@ -7,7 +7,7 @@ from __future__ import annotations
 import json
 import os
 from dataclasses import dataclass
-from datetime import datetime
+from datetime import UTC, datetime
 from pathlib import Path

 from sqlalchemy import select
@@ -148,6 +148,7 @@ class CredentialService:
            return None
        plaintext = self.crypto.decrypt(row.encrypted_blob)
        netscape = _to_netscape(plaintext)
+        netscape = _augment_cookies(platform, netscape)
        self.cookies_dir.mkdir(parents=True, exist_ok=True)
        out = self.cookies_dir / f"{platform}_cookies.txt"
        out.write_text(netscape)
@@ -162,6 +163,32 @@ class CredentialService:
            return None
        return self.crypto.decrypt(row.encrypted_blob)

+    async def mark_verified(self, platform: str) -> datetime | None:
+        """Stamp last_verified=now after a successful verify. Returns the
+        timestamp, or None if the credential is gone."""
+        row = (await self.session.execute(
+            select(Credential).where(Credential.platform == platform)
+        )).scalar_one_or_none()
+        if row is None:
+            return None
+        ts = datetime.now(UTC)
+        row.last_verified = ts
+        await self.session.commit()
+        return ts
+
+
+def _augment_cookies(platform: str, netscape: str) -> str:
+    """Delegate to the platform's `augment_cookies` hook if one is
+    registered (subscribestar, hentaifoundry, etc. — see
+    `services/platforms/<name>.py`). No-op when the platform doesn't
+    register a hook (Patreon, DeviantArt). Centralizing the
+    quirks-per-platform in the platforms package means adding a new
+    platform's cookie quirks doesn't require touching this file."""
+    info = PLATFORMS.get(platform)
+    if info is None or info.augment_cookies is None:
+        return netscape
+    return info.augment_cookies(netscape)
+

 def _to_netscape(plaintext: str) -> str:
    """Accept either Netscape-format text (the extension's output) or a
@@ -25,9 +25,18 @@ from sqlalchemy.orm import joinedload

 from ..models import Artist, DownloadEvent, Source
 from .credential_service import CredentialService
-from .gallery_dl import GalleryDLService, SourceConfig
+from .gallery_dl import (
+    BACKFILL_SKIP_VALUE,
+    BACKFILL_TIMEOUT_SECONDS,
+    TICK_SKIP_VALUE,
+    ErrorType,
+    GalleryDLService,
+    SourceConfig,
+)
 from .importer import Importer
 from .patreon_resolver import resolve_campaign_id
+from .platforms import auth_type_for
+from .scheduler_service import set_platform_cooldown

 log = logging.getLogger(__name__)

@@ -83,6 +92,18 @@ class DownloadService:
        ctx = setup

        source_config = SourceConfig.from_dict(ctx["config_overrides"] or {})
+        # alembic 0031 / plan #544: derive skip_value + timeout from the
+        # source's backfill_runs_remaining counter. When > 0, walk the full
+        # post history (skip: True + 1800s); when 0, exit gallery-dl after
+        # 20 contiguous archived items (skip: "exit:20" + the default
+        # 870s). Operator sets backfill via POST /api/sources/{id}/backfill.
+        backfill_remaining = ctx.get("backfill_runs_remaining", 0) or 0
+        if backfill_remaining > 0:
+            skip_value: bool | str = BACKFILL_SKIP_VALUE
+            source_config.timeout = BACKFILL_TIMEOUT_SECONDS
+        else:
+            skip_value = TICK_SKIP_VALUE
+
        effective_url = _effective_url(
            ctx["platform"], ctx["url"], ctx["config_overrides"] or {}
        )
@@ -94,6 +115,7 @@ class DownloadService:
            source_config=source_config,
            cookies_path=ctx["cookies_path"],
            auth_token=ctx["auth_token"],
+            skip_value=skip_value,
        )

        resolved_campaign_id: str | None = None
@@ -120,6 +142,7 @@ class DownloadService:
                        source_config=source_config,
                        cookies_path=ctx["cookies_path"],
                        auth_token=ctx["auth_token"],
+                        skip_value=skip_value,
                    )

        return await self._phase3_persist(
@@ -155,6 +178,13 @@ class DownloadService:
            return {"status": "in_flight", "event_id": existing.id}
        if existing and existing.status == "pending":
            existing.status = "running"
+            # Reset started_at on the pending→running transition so the
+            # recovery sweep (DOWNLOAD_STALL_THRESHOLD_MINUTES, 30 min)
+            # measures from real start, not from enqueue. On heavy-queue
+            # days a freshly-promoted event whose original started_at
+            # predated the cutoff would otherwise get swept mid-flight,
+            # racing phase3's commit. Audit 2026-06-02.
+            existing.started_at = datetime.now(UTC)
            await self.async_session.commit()
            event_id = existing.id
        else:
@@ -165,7 +195,12 @@ class DownloadService:
            event_id = ev.id

        artist = source.artist
-        if source.platform in ("discord", "pixiv"):
+        # Drive cookies-vs-token selection from the platform registry's
+        # auth_type so a new 7th token-platform automatically picks the
+        # right credential path. The hardcoded tuple here used to drift
+        # out of sync with credential_service's auth_type_for(). Audit
+        # 2026-06-02.
+        if auth_type_for(source.platform) == "token":
            cookies_path = None
            auth_token = await self.cred_service.get_token(source.platform)
        else:
@@ -184,6 +219,7 @@ class DownloadService:
            "config_overrides": dict(source.config_overrides or {}),
            "cookies_path": cookies_path,
            "auth_token": auth_token,
+            "backfill_runs_remaining": source.backfill_runs_remaining or 0,
        }

    async def _phase3_persist(
@@ -237,6 +273,40 @@ class DownloadService:
                    bytes_downloaded += path.stat().st_size  # noqa: ASYNC240
                except OSError:
                    pass
+                # Enqueue thumbnail + ML for newly-attached images, matching
+                # the filesystem-import path (tasks/import_file.py:228-239).
+                # Importer.attach_in_place deliberately skips inline thumb
+                # generation to keep the import queue moving; the calling
+                # task is responsible for the enqueue. Operator-flagged
+                # 2026-06-01: without this, every downloaded image stayed
+                # at thumbnail_path=NULL until a periodic backfill swept
+                # it up, surfacing as broken-thumbnail tiles in the gallery
+                # for hours after a download landed. Lazy import to avoid
+                # circular-import risk between this service and the
+                # tasks/* modules that import it.
+                from ..tasks.ml import tag_and_embed
+                from ..tasks.thumbnail import generate_thumbnail
+                ids = list(result.member_image_ids)
+                if result.image_id is not None and result.image_id not in ids:
+                    ids.append(result.image_id)
+                for img_id in ids:
+                    generate_thumbnail.delay(img_id)
+                    tag_and_embed.delay(img_id)
+            elif result.status == "attached":
+                # Non-media or extracted archive captured as PostAttachment
+                # (FC-2d-iii). The canonical copy lives in the attachments
+                # store; the original download path is now redundant —
+                # mirror duplicate_hash cleanup so we don't keep two copies.
+                # Operator-flagged 2026-06-02 (Lustria OST zip).
+                import_summary["attached"] += 1
+                try:
+                    bytes_downloaded += path.stat().st_size  # noqa: ASYNC240
+                except OSError:
+                    pass
+                try:
+                    path.unlink(missing_ok=True)  # noqa: ASYNC240
+                except OSError:
+                    pass
            elif result.status == "skipped" and result.skip_reason and result.skip_reason.value in (
                "duplicate_hash", "duplicate_phash",
            ):
@@ -245,6 +315,29 @@ class DownloadService:
                    path.unlink(missing_ok=True)  # noqa: ASYNC240
                except OSError:
                    pass
+            elif result.status == "skipped":
+                # Soft skip (too_small, too_transparent, invalid_image) —
+                # the file just didn't qualify, not a download/ingest
+                # failure. Don't flag the run as error; the file stays
+                # on disk for operator inspection.
+                import_summary["skipped"] += 1
+            elif result.status == "failed":
+                # Hard failure (today only: archive probe crash/timeout).
+                # The original archive sits in /images/ as an orphan; the
+                # filesystem scanner would re-import and re-crash on the
+                # same file, so delete the source file and surface the
+                # error in import_summary. Audit 2026-06-02.
+                import_summary["errors"] += 1
+                try:
+                    path.unlink(missing_ok=True)  # noqa: ASYNC240
+                except OSError:
+                    pass
+            elif result.status == "refreshed":
+                # Currently unreachable from attach_in_place (the download
+                # path never runs in deep=True mode), but the importer's
+                # ImportResult contract enumerates it. Treat the same as
+                # 'attached' — work happened, no error. Audit 2026-06-02.
+                import_summary["attached"] += 1
            else:
                import_summary["errors"] += 1

@@ -258,12 +351,21 @@ class DownloadService:
        run_stats["quarantined_count"] = dl_result.files_quarantined
        stderr_summary = self.gdl._extract_errors_warnings(dl_result.stderr)

-        status = "ok" if (dl_result.success and import_summary["errors"] == 0) else "error"
+        # Plan #544: PARTIAL means the run downloaded ≥1 file but the
+        # subprocess didn't finish in budget (typically wall-clock timeout
+        # mid-walk). Real work happened; the next tick continues via
+        # gallery-dl's archive. NOT a failure for status purposes.
+        if dl_result.success and import_summary["errors"] == 0:
+            status = "ok"
+        elif dl_result.error_type == ErrorType.PARTIAL and import_summary["errors"] == 0:
+            status = "ok"
+        else:
+            status = "error"
        ev.status = status
        ev.finished_at = datetime.now(UTC)
        ev.files_count = import_summary["attached"]
        ev.bytes_downloaded = bytes_downloaded
-        ev.error = dl_result.error_message if not dl_result.success else None
+        ev.error = dl_result.error_message if status == "error" else None
        ev.metadata_ = {
            "run_stats": run_stats,
            "error_type": dl_result.error_type.value if dl_result.error_type else None,
@@ -276,18 +378,54 @@ class DownloadService:
        }
        await self._update_source_health(
            source_id=ctx["source_id"], status=status, error_message=ev.error,
+            error_type=dl_result.error_type.value if dl_result.error_type else None,
        )
+        # Plan #544: backfill lifecycle — auto-complete when a clean
+        # backfill run drained the queue (gallery-dl exited 0 + zero files
+        # downloaded means there was nothing to fetch); otherwise decrement
+        # the counter. Next tick falls back to tick mode once it hits 0.
+        #
+        # Audit 2026-06-02 gating: VALIDATION_FAILED also exits the
+        # subprocess with return_code=0 and files_downloaded=0 (every
+        # file was quarantined), which used to match the auto-complete
+        # predicate exactly — zeroing the operator's armed budget on
+        # the FIRST quarantine run instead of decrementing. Require
+        # dl_result.success + no error_type so only genuinely-empty
+        # successful runs drain the counter.
+        backfill_remaining = ctx.get("backfill_runs_remaining", 0) or 0
+        if backfill_remaining > 0:
+            src = (await self.async_session.execute(
+                select(Source).where(Source.id == ctx["source_id"])
+            )).scalar_one()
+            queue_drained = (
+                dl_result.success
+                and dl_result.error_type is None
+                and dl_result.return_code == 0
+                and dl_result.files_downloaded == 0
+            )
+            if queue_drained:
+                src.backfill_runs_remaining = 0
+            else:
+                src.backfill_runs_remaining = max(0, backfill_remaining - 1)
        await self.async_session.commit()
        return event_id

    async def _update_source_health(
        self, *, source_id: int, status: str, error_message: str | None,
+        error_type: str | None = None,
    ) -> None:
        """FC-3d: update Source.{consecutive_failures, last_error, last_checked_at}.

        ok      -> failures = 0, error = None, checked_at = now
        error   -> failures += 1, error = error_message, checked_at = now
        skipped -> failures unchanged, error = None, checked_at = now
+
+        When error_type == 'rate_limited', also stamps a platform-wide
+        cooldown via scheduler_service.set_platform_cooldown so the next
+        scan tick skips every source on this platform until the cooldown
+        expires. Preventive half of the burst-prevention pair —
+        consecutive_failures still backs the offending source off across
+        ticks.
        """
        source = (await self.async_session.execute(
            select(Source).where(Source.id == source_id)
@@ -296,9 +434,17 @@ class DownloadService:
        if status == "ok":
            source.consecutive_failures = 0
            source.last_error = None
+            # alembic 0032 — clear the failure-class chip on success.
+            source.error_type = None
        elif status == "error":
            source.consecutive_failures = (source.consecutive_failures or 0) + 1
            source.last_error = error_message
+            # alembic 0032 — stamp the failure-class so FailingSourcesCard
+            # can render a colored chip and operators can bulk-triage
+            # by error class without opening Logs per row.
+            source.error_type = error_type
+            if error_type == "rate_limited":
+                await set_platform_cooldown(self.async_session, source.platform)
        elif status == "skipped":
            source.last_error = None
        source.last_checked_at = now
@@ -16,6 +16,7 @@ from sqlalchemy.ext.asyncio import AsyncSession

 from ..models import Artist, Source
 from ..utils.slug import slugify
+from .source_service import NEW_SOURCE_BACKFILL_RUNS


 class UnknownPlatformError(Exception):
@@ -86,6 +87,67 @@ class ExtensionService:
            "created_artist": created_artist,
        }

+    async def probe(self, url: str) -> dict:
+        """Read-only resolution of a creator-page URL against the FC DB.
+        Returns one of:
+          - {state: 'unknown_platform'}            — URL didn't match any
+            platform's strict artist-page pattern
+          - {state: 'new',          platform, slug} — would create both
+            artist and source on quick-add
+          - {state: 'artist_match', platform, slug, artist}
+                                                   — artist exists, this
+            exact URL isn't a Source yet (collapses the sidecar-synthetic
+            case too — the synthetic anchor counts as an existing artist
+            row but not as a pollable Source for this URL)
+          - {state: 'source_match', platform, slug, artist, source}
+                                                   — exact (artist, platform,
+            url) Source already exists
+
+        Side-effect-free: two SELECTs at most.
+        """
+        try:
+            platform, raw_slug = self._derive(url)
+        except (UnknownPlatformError, InvalidUrlError):
+            return {"state": "unknown_platform"}
+
+        slug = slugify(raw_slug)
+        artist = (await self.session.execute(
+            select(Artist).where(Artist.slug == slug)
+        )).scalar_one_or_none()
+        if artist is None:
+            return {"state": "new", "platform": platform, "slug": slug}
+
+        artist_payload = {"id": artist.id, "name": artist.name, "slug": artist.slug}
+
+        source = (await self.session.execute(
+            select(Source).where(
+                Source.artist_id == artist.id,
+                Source.platform == platform,
+                Source.url == url,
+            )
+        )).scalar_one_or_none()
+        if source is None:
+            return {
+                "state": "artist_match",
+                "platform": platform,
+                "slug": slug,
+                "artist": artist_payload,
+            }
+
+        return {
+            "state": "source_match",
+            "platform": platform,
+            "slug": slug,
+            "artist": artist_payload,
+            "source": {
+                "id": source.id,
+                "artist_id": source.artist_id,
+                "platform": source.platform,
+                "url": source.url,
+                "enabled": source.enabled,
+            },
+        }
+
    def _derive(self, url: str) -> tuple[str, str]:
        if not isinstance(url, str) or not url.strip():
            raise InvalidUrlError("url is empty")
@@ -143,9 +205,16 @@ class ExtensionService:
            return existing, False
        sp = await self.session.begin_nested()
        try:
+            # New subscription sources arm a few backfill runs so the
+            # first ticks walk the full history (otherwise gallery-dl's
+            # exit:20 short-circuits before the archive is built).
+            # Mirrors SourceService.create — without it, Firefox quick-
+            # add on a creator with >20 unsynced posts would surface
+            # as "check failed" with no diagnosis. Audit 2026-06-02.
            src = Source(
                artist_id=artist_id, platform=platform,
                url=url, enabled=True,
+                backfill_runs_remaining=NEW_SOURCE_BACKFILL_RUNS,
            )
            self.session.add(src)
            await self.session.flush()
@@ -39,19 +39,69 @@ class ErrorType(StrEnum):
    HTTP_ERROR = "http_error"
    UNSUPPORTED_URL = "unsupported_url"
    VALIDATION_FAILED = "validation_failed"
+    # Run made real progress (downloaded ≥1 file) but did not finish in the
+    # subprocess budget. Distinct from UNKNOWN_ERROR — the downstream status
+    # mapping classifies this as "ok" because the next tick continues.
+    PARTIAL = "partial"
    UNKNOWN_ERROR = "unknown_error"


+# Tick mode (routine cron polls): skip ≤20 contiguous already-archived
+# items, then exit gallery-dl. Established subscription with zero new
+# content exits in ~30s of HEAD requests instead of walking to the bottom
+# of the post history (which can be hours for prolific creators). 20 (not
+# 5) is operator-set headroom against any edge case where paywalled or
+# otherwise-non-downloadable items might interleave with archived ones —
+# 20 contiguous HEADs is still negligible.
+TICK_SKIP_VALUE = "exit:20"
+
+# Backfill mode (operator-triggered deep scan): walk the full history.
+# Source.backfill_runs_remaining > 0 selects this mode; the longer
+# timeout below absorbs creators with thousands of posts.
+#
+# 30 seconds shy of Celery's hard `time_limit=1200` on download_source
+# (tasks/download.py:33). subprocess.run MUST raise TimeoutExpired
+# before Celery SIGKILLs the worker — same rationale as the tick
+# default at line 74. The audit (2026-06-02) caught this at 1800,
+# guaranteeing SIGKILL on any backfill that ran to its subprocess
+# budget: stdout/stderr lost, backfill_runs_remaining never
+# decrements, recovery sweep stamps generic "stranded" 30 min later.
+# Recreates the exact Knuxy #38275 failure mode the tick 870s default
+# was added to prevent. backfill_runs_remaining=3 still gives ~58
+# minutes of cumulative walk across three runs for prolific creators.
+BACKFILL_SKIP_VALUE = True
+BACKFILL_TIMEOUT_SECONDS = 1170
+
+
+# 30 seconds shy of download_source's Celery soft_time_limit (900s, see
+# tasks/download.py:32). subprocess.run MUST raise TimeoutExpired before
+# Celery raises SoftTimeLimitExceeded — otherwise Celery wins the race,
+# SIGKILLs the worker, in-memory stdout/stderr is lost, and the
+# DownloadEvent ends up empty-logged with "stranded by recovery sweep"
+# 18 minutes later (operator-flagged 2026-05-31, Knuxy event #38275).
+# The 30s buffer absorbs scheduler jitter / GC pauses without making
+# legitimately-long-running syncs timeout-friendlier. Per-source bumps
+# still live in source.config_overrides for legitimately long syncs.
+_DEFAULT_GDL_TIMEOUT_SECONDS = 870
+
+
@dataclass
 class SourceConfig:
+    """Per-source overrides loaded from Source.config_overrides JSON.
+
+    Note: the gallery-dl `skip` value (tick vs backfill, see TICK_SKIP_VALUE /
+    BACKFILL_SKIP_VALUE) is NOT carried here — it derives from the
+    Source.backfill_runs_remaining column at the download_service layer
+    and is passed to _build_config_for_source as `skip_value`. Same for
+    the per-run subprocess timeout.
+    """
    content_types: list[str] = field(default_factory=lambda: ["all"])
    sleep: float | None = None
    sleep_request: float | None = None
    directory_pattern: str | None = None
    filename_pattern: str | None = None
-    skip_existing: bool = True
    save_metadata: bool = True
-    timeout: int = 3600
+    timeout: int = _DEFAULT_GDL_TIMEOUT_SECONDS

    @classmethod
    def from_dict(cls, data: dict) -> SourceConfig:
@@ -61,9 +111,8 @@ class SourceConfig:
            sleep_request=data.get("sleep_request"),
            directory_pattern=data.get("directory_pattern"),
            filename_pattern=data.get("filename_pattern"),
-            skip_existing=data.get("skip_existing", True),
            save_metadata=data.get("save_metadata", True),
-            timeout=data.get("timeout", 3600),
+            timeout=data.get("timeout", _DEFAULT_GDL_TIMEOUT_SECONDS),
        )


@@ -219,6 +268,25 @@ class GalleryDLService:
                "part-directory": str(self._config_dir / "temp"),
                "retries": 3,
                "timeout": 120.0,
+                # Forward Patreon as Referer/Origin to yt-dlp when it
+                # fetches video manifests. Operator-flagged 2026-06-01
+                # (DaferQ patreon): video posts hosted on Mux carry a JWT
+                # playback restriction that checks Referer/Origin on every
+                # request — not just the token signature. gallery-dl's
+                # HEAD probe to stream.mux.com returns 200 (the token is
+                # valid), but yt-dlp's actual GET-with-Range to fetch the
+                # m3u8 manifest 403s because yt-dlp sends its own default
+                # Referer, which Mux's policy rejects. Forcing the right
+                # headers fixes the headers-only case; Mux IP-range
+                # restrictions are unfixable from here.
+                "ytdl": {
+                    "raw-options": {
+                        "http_headers": {
+                            "Referer": "https://www.patreon.com/",
+                            "Origin": "https://www.patreon.com",
+                        },
+                    },
+                },
            },
            "output": {"progress": True},
        }
@@ -233,7 +301,18 @@ class GalleryDLService:
        platform: str,
        source_config: SourceConfig,
        artist_slug: str,
+        skip_value: bool | str = BACKFILL_SKIP_VALUE,
    ) -> dict:
+        """`skip_value` controls gallery-dl's archive-walk behavior:
+            - True (BACKFILL_SKIP_VALUE): walk full post history, skipping
+              archived items but continuing past them. Used in backfill mode.
+            - "exit:20" (TICK_SKIP_VALUE): exit gallery-dl after 20
+              contiguous archived items. Used in tick (routine catch-up)
+              mode for fast no-op syncs on creators with deep history.
+            - False: don't skip — redownload everything (not used in FC).
+        The caller (download_service) chooses based on
+        Source.backfill_runs_remaining.
+        """
        config = json.loads(json.dumps(self._get_default_config()))  # deep copy

        destination = str(self.images_root / artist_slug / platform)
@@ -243,7 +322,7 @@ class GalleryDLService:
            config["extractor"]["sleep"] = source_config.sleep
        if source_config.sleep_request is not None:
            config["extractor"]["sleep-request"] = source_config.sleep_request
-        config["extractor"]["skip"] = source_config.skip_existing
+        config["extractor"]["skip"] = skip_value

        if source_config.save_metadata:
            config["extractor"]["postprocessors"] = [
@@ -360,7 +439,17 @@ class GalleryDLService:
        if return_code in (1, 4) and (skip_line_count > 0 or has_skip_text) and not has_actual_error:
            return ErrorType.NO_NEW_CONTENT, "No new content to download"

-        if return_code in (1, 4) and not has_actual_error:
+        # Tier-gated classification used to require `return_code in (1, 4)`,
+        # which silently fell through to UNKNOWN_ERROR when gallery-dl
+        # returned a different exit code for mixed-failure runs (e.g.
+        # paywall warnings + a missing yt-dlp dep flipping the exit bits).
+        # The artist then surfaced as "needs attention" purely because a
+        # paywall blocked posts the operator wasn't paying to see —
+        # operator-flagged 2026-05-31. Now: if no source-level error
+        # category fired AND tier-gated warnings are present, classify
+        # as TIER_LIMITED regardless of return code. Same priority order
+        # as before (auth/rate/access/not_found/network/http still win).
+        if not has_actual_error:
            tier_gated_lines = [
                line for line in combined.split("\n")
                if "][warning]" in line and "not allowed to view post" in line
@@ -372,6 +461,22 @@ class GalleryDLService:
                    f"Subscription tier does not grant access to {count} post{'s' if count != 1 else ''}",
                )

+        # Partial-success: the subprocess exited non-zero (typically because
+        # the wall-clock timeout fired mid-walk), but it had downloaded ≥1
+        # file by then and no source-level error category fired. The work
+        # the run DID do is real; gallery-dl's archive will pick up where
+        # it left off on the next tick. Mapped to status="ok" downstream
+        # (download_service.py) so this doesn't flag the source as
+        # "needs attention." Operator-flagged 2026-06-01 after a Knuxy
+        # patreon run downloaded hundreds of files then ran red on timeout.
+        files_downloaded = self._count_downloaded_files(stdout)
+        if not has_actual_error and files_downloaded > 0:
+            return (
+                ErrorType.PARTIAL,
+                f"Downloaded {files_downloaded} file{'s' if files_downloaded != 1 else ''}; "
+                "run did not complete in budget — next tick will continue",
+            )
+
        return ErrorType.UNKNOWN_ERROR, f"Unknown error (return code: {return_code})"

    def _count_downloaded_files(self, stdout: str) -> int:
@@ -523,6 +628,7 @@ class GalleryDLService:
        source_config: SourceConfig | None = None,
        cookies_path: str | None = None,
        auth_token: str | None = None,
+        skip_value: bool | str = BACKFILL_SKIP_VALUE,
    ) -> DownloadResult:
        start_time = time.time()
        started_at = datetime.now(UTC).isoformat()
@@ -530,7 +636,9 @@ class GalleryDLService:
        if source_config is None:
            source_config = SourceConfig()

-        config = self._build_config_for_source(platform, source_config, artist_slug)
+        config = self._build_config_for_source(
+            platform, source_config, artist_slug, skip_value=skip_value,
+        )

        if cookies_path:
            config["extractor"]["cookies"] = cookies_path
@@ -632,13 +740,57 @@ class GalleryDLService:
                started_at=started_at, completed_at=completed_at,
            )

-        except subprocess.TimeoutExpired:
+        except subprocess.TimeoutExpired as e:
            duration = time.time() - start_time
-            log.error("Download timeout for %s/%s after %.1fs", artist_slug, platform, duration)
+            # subprocess.run(text=True) makes these str if non-None, but the
+            # caller may have raised TimeoutExpired manually with None or
+            # bytes (tests do); coerce both cases to str.
+            partial_stdout = e.stdout or ""
+            partial_stderr = e.stderr or ""
+            if isinstance(partial_stdout, bytes):
+                partial_stdout = partial_stdout.decode("utf-8", "replace")
+            if isinstance(partial_stderr, bytes):
+                partial_stderr = partial_stderr.decode("utf-8", "replace")
+
+            files_so_far = self._count_downloaded_files(partial_stdout)
+            written_so_far = [str(p) for p in self._written_paths(partial_stdout)]
+            stderr_lines = partial_stderr.strip().splitlines()
+            tail_hint = stderr_lines[-1] if stderr_lines else "no stderr output"
+
+            # If the partial output already shows a rate-limit pattern, the
+            # timeout was almost certainly gallery-dl spinning on retries —
+            # promote to RATE_LIMITED so _update_source_health stamps the
+            # platform cooldown (same code path as a clean-exit rate limit).
+            # Otherwise stay TIMEOUT and let the captured stdout/stderr +
+            # files_so_far tell the operator whether it was "lots of
+            # content" vs "stuck retrying" vs "hung silent".
+            combined = (partial_stdout + "\n" + partial_stderr).lower()
+            if any(p in combined for p in self.RATE_LIMIT_PATTERNS):
+                error_type = ErrorType.RATE_LIMITED
+                error_message = (
+                    f"Rate-limited and never completed within "
+                    f"{source_config.timeout}s ({files_so_far} files written)"
+                )
+            else:
+                error_type = ErrorType.TIMEOUT
+                error_message = (
+                    f"Download timed out after {source_config.timeout}s — "
+                    f"{files_so_far} file(s) written; last stderr: {tail_hint}"
+                )
+
+            log.error(
+                "Download timeout for %s/%s after %.1fs (%d files written, "
+                "last stderr: %s)",
+                artist_slug, platform, duration, files_so_far, tail_hint,
+            )
+
            return DownloadResult(
                success=False, url=url, artist_slug=artist_slug, platform=platform,
-                error_type=ErrorType.TIMEOUT,
-                error_message=f"Download timed out after {source_config.timeout} seconds",
+                files_downloaded=files_so_far,
+                written_paths=written_so_far,
+                stdout=partial_stdout, stderr=partial_stderr,
+                return_code=-1,  # killed by timeout, no real exit code
+                error_type=error_type, error_message=error_message,
                duration_seconds=duration,
                started_at=started_at,
                completed_at=datetime.now(UTC).isoformat(),
@@ -658,3 +810,70 @@ class GalleryDLService:
                Path(temp_config_path).unlink()  # noqa: ASYNC240
            except Exception:
                pass
+
+    async def verify(
+        self,
+        url: str,
+        artist_slug: str,
+        platform: str,
+        source_config: SourceConfig | None = None,
+        cookies_path: str | None = None,
+        auth_token: str | None = None,
+        timeout: float = 45.0,  # noqa: ASYNC109 — subprocess.run timeout, not a coroutine deadline
+    ) -> tuple[bool, str]:
+        """Test that credentials authenticate against `url` WITHOUT
+        downloading anything. Runs gallery-dl in --simulate mode limited
+        to the first item; if auth is bad the extractor errors before it
+        can list, which _categorize_error flags as AUTH_ERROR. Returns
+        (ok, message). Used by the credential Verify button."""
+        if source_config is None:
+            source_config = SourceConfig()
+        config = self._build_config_for_source(platform, source_config, artist_slug)
+        if cookies_path:
+            config["extractor"]["cookies"] = cookies_path
+        if auth_token and platform == "discord":
+            config["extractor"].setdefault("discord", {})["token"] = auth_token
+        if auth_token and platform == "pixiv":
+            config["extractor"].setdefault("pixiv", {})["refresh-token"] = auth_token
+
+        with tempfile.NamedTemporaryFile(
+            mode="w", suffix=".json", delete=False, dir=str(self._config_dir),
+        ) as fh:
+            json.dump(config, fh, indent=2)
+            temp_config_path = fh.name
+        try:
+            cmd = [
+                sys.executable, "-m", "gallery_dl",
+                "--config", temp_config_path,
+                "--simulate", "--range", "1-1", "--verbose", url,
+            ]
+            loop = asyncio.get_running_loop()
+            proc = await loop.run_in_executor(
+                None,
+                lambda: subprocess.run(
+                    cmd, capture_output=True, text=True, timeout=timeout,
+                ),
+            )
+            etype, msg = self._categorize_error(proc.returncode, proc.stdout, proc.stderr)
+            # TIER_LIMITED proves auth worked — gallery-dl reached the
+            # post, was told it's tier-gated. The download path treats
+            # this as success (line 712); verify must too, or operators
+            # rotate working cookies for no reason. Audit 2026-06-02.
+            if proc.returncode == 0 or etype in (
+                ErrorType.NO_NEW_CONTENT, ErrorType.TIER_LIMITED,
+            ):
+                return True, "Credentials valid — the feed authenticated."
+            if etype == ErrorType.AUTH_ERROR:
+                return False, msg
+            # Network / not-found / rate-limit / unknown: inconclusive,
+            # not a definitive credential failure. Surface the reason.
+            return False, f"Could not confirm ({etype.value}): {msg}"
+        except subprocess.TimeoutExpired:
+            return False, f"Verification timed out after {timeout:.0f}s"
+        except Exception as exc:  # noqa: BLE001
+            return False, f"Verification error: {exc}"
+        finally:
+            try:
+                Path(temp_config_path).unlink()  # noqa: ASYNC240
+            except Exception:
+                pass
@@ -20,8 +20,9 @@ from datetime import datetime

 from sqlalchemy import Select, and_, exists, func, or_, select
 from sqlalchemy.ext.asyncio import AsyncSession
+from sqlalchemy.orm import aliased

-from ..models import Artist, ImageProvenance, ImageRecord, Post, Source, Tag
+from ..models import Artist, ImageProvenance, ImageRecord, Post, Tag
 from ..models.tag import image_tag

 CURSOR_SEPARATOR = "|"
@@ -90,9 +91,27 @@ class TimelineBucket:
    count: int


-def thumbnail_url(sha256_hex: str, mime: str) -> str:
-    # Quart serves /images/* via the frontend blueprint (FC-1); thumbnails go
-    # under /images/thumbs/. The MIME determines the extension.
+def thumbnail_url(thumbnail_path: str | None, sha256_hex: str, mime: str) -> str:
+    """Return the URL to fetch a thumbnail.
+
+    Prefers the stored thumbnail_path verbatim — Quart serves /images/*
+    1:1 from the volume (frontend.py:20-36), so the URL IS the disk
+    path. Falls back to deriving from (sha256, mime) only when the
+    record's thumbnail_path is NULL (thumbnailer hasn't run yet); that
+    URL will 404 until backfill catches it, same as before the path
+    was tracked.
+
+    Pre-2026-05-30 this was derived only from (sha256, mime), which
+    disagreed with the actual on-disk extension when the thumbnailer
+    chose its format from transparency rather than MIME — every PNG
+    source without alpha (extension was .jpg on disk) and every WebP
+    source with alpha (extension was .png on disk) silently 404'd
+    despite the thumbnail file existing.
+    """
+    if thumbnail_path:
+        return thumbnail_path
+    # Fallback for records with no thumbnail recorded yet — preserves
+    # prior behavior (URL exists but 404s until backfill regenerates).
    ext = ".png" if mime in ("image/png", "image/gif") else ".jpg"
    bucket = sha256_hex[:3]
    return f"/images/thumbs/{bucket}/{sha256_hex}{ext}"
@@ -115,10 +134,23 @@ def _provenance_clause(post_id, artist_id):
            ImageProvenance.post_id == post_id,
        )
    if artist_id is not None:
+        # Use Post.artist_id (alembic 0030 denormalized column) instead
+        # of joining through ImageProvenance.source_id → Source.artist_id.
+        # The denormalization is the always-present linkage; the source
+        # path now drops NULL-source provenance rows (filesystem-imported
+        # content) which would otherwise vanish from artist-filtered
+        # gallery views.
+        # ALIAS Post: the gallery query outer-joins Post on
+        # ImageRecord.primary_post_id (`_outer_join_primary_post`).
+        # SQLAlchemy would otherwise correlate a bare `Post` reference
+        # in this EXISTS subquery to that outer Post (which is NULL for
+        # images with no primary post), and the filter would silently
+        # match nothing.
+        post_inner = aliased(Post)
        return exists().where(
            ImageProvenance.image_record_id == ImageRecord.id,
-            ImageProvenance.source_id == Source.id,
-            Source.artist_id == artist_id,
+            ImageProvenance.post_id == post_inner.id,
+            post_inner.artist_id == artist_id,
        )
    return None

@@ -198,7 +230,7 @@ class GalleryService:
                created_at=record.created_at,
                effective_date=eff_date,
                posted_at=posted_at,
-                thumbnail_url=thumbnail_url(record.sha256, record.mime),
+                thumbnail_url=thumbnail_url(record.thumbnail_path, record.sha256, record.mime),
                artist=artists.get(record.id),
            )
            for record, posted_at, eff_date in rows
@@ -306,7 +338,7 @@ class GalleryService:
            "integrity_status": record.integrity_status,
            "created_at": record.created_at.isoformat(),
            "posted_at": posted_at.isoformat() if posted_at else None,
-            "thumbnail_url": thumbnail_url(record.sha256, record.mime),
+            "thumbnail_url": thumbnail_url(record.thumbnail_path, record.sha256, record.mime),
            "image_url": f"/images/{record.path.split('/images/', 1)[-1]}",
            "artist": (
                {"id": artist.id, "name": artist.name, "slug": artist.slug}
@@ -30,6 +30,7 @@ from ..models import (
    PostAttachment,
    Source,
 )
+from ..utils import safe_probe
 from ..utils.paths import derive_subdir, derive_top_level_artist, hash_suffixed_name
 from ..utils.phash import compute_phash, find_similar
 from ..utils.sidecar import find_sidecar, parse_sidecar
@@ -203,6 +204,32 @@ class Importer:
                (phash, width or 0, height or 0, image_id)
            )

+    def _get_or_create(self, stmt, factory):
+        """Race-safe find-or-create. Run `stmt` (scalar_one_or_none); if a
+        row exists, return it. Otherwise open a savepoint and INSERT
+        ``factory()``; on IntegrityError (a concurrent worker inserted the
+        same row first) roll the savepoint back — NOT the outer transaction,
+        which would lose the surrounding scan's progress — and re-run `stmt`
+        (scalar_one) to return the row the other worker created.
+
+        Centralizes the pattern shared by _find_or_create_source and
+        _find_or_create_post. The plain SELECT-then-INSERT version lost
+        races under the 5-min recovery sweep (operator-flagged
+        2026-05-26)."""
+        existing = self.session.execute(stmt).scalar_one_or_none()
+        if existing is not None:
+            return existing
+        sp = self.session.begin_nested()
+        try:
+            row = factory()
+            self.session.add(row)
+            self.session.flush()
+            sp.commit()
+            return row
+        except IntegrityError:
+            sp.rollback()
+            return self.session.execute(stmt).scalar_one()
+
    def _find_or_create_source(
        self, *, artist_id: int, platform: str, url: str,
    ) -> Source:
@@ -221,53 +248,35 @@ class Importer:
        and re-select — the concurrent op just created the row we
        wanted, so the second select will find it.
        """
-        existing = self.session.execute(
-            select(Source).where(
-                Source.artist_id == artist_id,
-                Source.platform == platform,
-                Source.url == url,
-            )
-        ).scalar_one_or_none()
-        if existing is not None:
-            return existing
-        sp = self.session.begin_nested()
-        try:
-            row = Source(artist_id=artist_id, platform=platform, url=url)
-            self.session.add(row)
-            self.session.flush()
-            sp.commit()
-            return row
-        except IntegrityError:
-            sp.rollback()
-            return self.session.execute(
-                select(Source).where(
-                    Source.artist_id == artist_id,
-                    Source.platform == platform,
-                    Source.url == url,
-                )
-            ).scalar_one()
+        stmt = select(Source).where(
+            Source.artist_id == artist_id,
+            Source.platform == platform,
+            Source.url == url,
+        )
+        return self._get_or_create(
+            stmt,
+            lambda: Source(artist_id=artist_id, platform=platform, url=url),
+        )

-    def _source_for_sidecar(
-        self, *, artist_id: int, platform: str, artist_slug: str,
-    ) -> Source:
-        """Filesystem-import sidecar Source resolver.
+    def _lookup_source_for_sidecar(
+        self, *, artist_id: int, platform: str,
+    ) -> Source | None:
+        """Find the real subscription Source for (artist, platform), or
+        None if no subscription exists.

-        Source represents a subscription feed (one per artist+platform — the
-        gallery-dl URL polled by the FC-3 downloader). The filesystem importer
-        used to call _find_or_create_source(url=sd.post_url), which created
-        one Source row per post URL — 100s of junk Sources per artist, all
-        with enabled=True, polluting the artist detail page and tricking the
-        subscription checker into trying to poll patreon post URLs as feeds.
-        Operator-flagged 2026-05-26.
-
-        New behaviour: if any Source row exists for (artist_id, platform),
-        reuse it regardless of its URL — the artist's real subscription Source
-        (created by the downloader / extension / UI) is the canonical
-        attachment point for filesystem-imported posts. If none exists, create
-        ONE synthetic anchor with url='sidecar:<platform>:<artist_slug>' and
-        enabled=False (so the subscription checker doesn't poll it).
+        Pre-alembic-0030 this method would CREATE a synthetic
+        `sidecar:<platform>:<slug>` Source when no real one existed —
+        because `Post.source_id` was NOT NULL and the importer needed
+        something to attach Posts to. Alembic 0030 relaxed both
+        `Post.source_id` and `ImageProvenance.source_id` to nullable, so
+        synthetic anchors are obsolete; the importer now leaves
+        source_id as None when no subscription exists for the (artist,
+        platform). Operator-asked 2026-06-01: synthetic Sources had
+        leaked into the Subscriptions UI as phantom subscriptions and
+        the operator wanted the data model to truthfully say "this
+        content has no live subscription."
        """
-        existing = self.session.execute(
+        stmt = (
            select(Source)
            .where(
                Source.artist_id == artist_id,
@@ -275,63 +284,39 @@ class Importer:
            )
            .order_by(Source.id.asc())
            .limit(1)
-        ).scalar_one_or_none()
-        if existing is not None:
-            return existing
-        synthetic_url = f"sidecar:{platform}:{artist_slug}"
-        sp = self.session.begin_nested()
-        try:
-            row = Source(
-                artist_id=artist_id,
-                platform=platform,
-                url=synthetic_url,
-                enabled=False,
-            )
-            self.session.add(row)
-            self.session.flush()
-            sp.commit()
-            return row
-        except IntegrityError:
-            sp.rollback()
-            return self.session.execute(
-                select(Source)
-                .where(
-                    Source.artist_id == artist_id,
-                    Source.platform == platform,
-                )
-                .order_by(Source.id.asc())
-                .limit(1)
-            ).scalar_one()
+        )
+        return self.session.execute(stmt).scalar_one_or_none()

    def _find_or_create_post(
-        self, *, source_id: int, external_post_id: str,
+        self, *, source_id: int | None, external_post_id: str,
+        artist_id: int,
    ) -> Post:
-        """Race-safe find-or-create on `post` keyed by
-        (source_id, external_post_id). Mirrors `_find_or_create_source`
-        — same savepoint + IntegrityError-recovery pattern."""
-        existing = self.session.execute(
-            select(Post).where(
+        """Race-safe find-or-create on `post`. Keyed by
+        (source_id, external_post_id) when source_id is set — the
+        `uq_post_source_external_id` constraint guards. For NULL-source
+        posts the existence check matches on (artist_id, external_post_id),
+        which the partial unique index `uq_post_artist_external_id_null_source`
+        (alembic 0030) guards. Same savepoint + IntegrityError-recovery
+        pattern as the rest of the helpers."""
+        if source_id is not None:
+            stmt = select(Post).where(
                Post.source_id == source_id,
                Post.external_post_id == external_post_id,
            )
-        ).scalar_one_or_none()
-        if existing is not None:
-            return existing
-        sp = self.session.begin_nested()
-        try:
-            row = Post(source_id=source_id, external_post_id=external_post_id)
-            self.session.add(row)
-            self.session.flush()
-            sp.commit()
-            return row
-        except IntegrityError:
-            sp.rollback()
-            return self.session.execute(
-                select(Post).where(
-                    Post.source_id == source_id,
-                    Post.external_post_id == external_post_id,
-                )
-            ).scalar_one()
+        else:
+            stmt = select(Post).where(
+                Post.source_id.is_(None),
+                Post.artist_id == artist_id,
+                Post.external_post_id == external_post_id,
+            )
+        return self._get_or_create(
+            stmt,
+            lambda: Post(
+                source_id=source_id,
+                artist_id=artist_id,
+                external_post_id=external_post_id,
+            ),
+        )

    def import_one(self, source: Path) -> ImportResult:
        """Dispatch by kind. Media → normal pipeline. Archive → extract
@@ -371,12 +356,14 @@ class Importer:
            return None
        sd = parse_sidecar(data)
        platform = sd.platform or "unknown"
-        src = self._source_for_sidecar(
-            artist_id=artist.id, platform=platform, artist_slug=artist.slug,
+        src = self._lookup_source_for_sidecar(
+            artist_id=artist.id, platform=platform,
        )
        epid = sd.external_post_id or sc.stem
        return self._find_or_create_post(
-            source_id=src.id, external_post_id=epid,
+            source_id=src.id if src else None,
+            external_post_id=epid,
+            artist_id=artist.id,
        )

    def _capture_attachment(
@@ -387,10 +374,19 @@ class Importer:
            artist = self._resolve_artist(source)
            post = self._post_for_sidecar(source, artist)
        sha = _sha256_of(source)
-        existing = self.session.execute(
-            select(PostAttachment).where(PostAttachment.sha256 == sha)
-        ).scalar_one_or_none()
-        if existing is None:
+        select_existing = select(PostAttachment).where(PostAttachment.sha256 == sha)
+        existing = self.session.execute(select_existing).scalar_one_or_none()
+        if existing is not None:
+            self.session.commit()
+            return ImportResult(status="attached")
+        # Savepoint + IntegrityError recovery — PostAttachment.sha256 is
+        # UNIQUE, so two workers can both pass the SELECT and only the
+        # second INSERT fails. Without savepoint, the outer transaction
+        # poisons and the calling task crashes. attachments.store is
+        # sha-addressed so both workers race to write the same target
+        # path; shutil.copy2 + rename is idempotent. Audit 2026-06-02.
+        sp = self.session.begin_nested()
+        try:
            stored = self.attachments.store(source, sha)
            self.session.add(PostAttachment(
                post_id=post.id if post else None,
@@ -403,23 +399,67 @@ class Importer:
                size_bytes=source.stat().st_size,
            ))
            self.session.flush()
+            sp.commit()
+        except IntegrityError:
+            sp.rollback()
+            # Lost the race — the other worker's row is canonical.
+            self.session.execute(select_existing).scalar_one()
        self.session.commit()
        return ImportResult(status="attached")

-    def _import_archive(self, source: Path) -> ImportResult:
-        artist = self._resolve_artist(source)
-        post = self._post_for_sidecar(source, artist)
+    def _import_archive(
+        self, source: Path, *,
+        artist: Artist | None = None,
+        source_row: Source | None = None,
+    ) -> ImportResult:
+        # Layer-3 isolation: bomb-size guard + integrity test in a
+        # spawned child BEFORE extracting in this process. A
+        # decompression bomb or a native-lib crash on a malformed
+        # archive is contained to the child; we reject the file cleanly
+        # instead of OOMing/segfaulting the import worker. extract_archive
+        # is already fail-soft for plain exceptions, so this only adds
+        # the hard-crash protection.
+        #
+        # Audit 2026-06-02: optional artist/source_row kwargs let the
+        # download path thread its explicit subscription context
+        # through instead of having _resolve_artist re-derive from
+        # path-walk (which works by coincidence today because gallery-dl
+        # lays files out under /images/<artist_slug>/...). Filesystem
+        # import still calls bare _import_archive(source) and falls
+        # back to the path-walk derivation as before.
+        probe = safe_probe.probe_archive(source)
+        if not probe.ok:
+            if probe.crashed:
+                return ImportResult(
+                    status="failed",
+                    error=f"archive probe crashed/timed out: {probe.reason}",
+                )
+            # Clean rejection (bomb cap exceeded, integrity mismatch):
+            # still preserve the archive file itself as an attachment so
+            # nothing silently vanishes, matching extract_archive's
+            # fail-soft contract.
+            artist_use = artist if artist is not None else self._resolve_artist(source)
+            post = self._post_for_sidecar(source, artist_use)
+            self._capture_attachment(
+                source, post=post, artist=artist_use, resolved=True,
+            )
+            return ImportResult(status="attached")
+
+        artist_use = artist if artist is not None else self._resolve_artist(source)
+        post = self._post_for_sidecar(source, artist_use)
        member_ids: list[int] = []
        with extract_archive(source) as members:
            for _name, member_path in members:
                if not is_supported(member_path):
                    continue  # non-media preserved via the stored archive
-                res = self._import_media(member_path, source)
+                res = self._import_media(
+                    member_path, source, explicit_source=source_row,
+                )
                if res.status in ("imported", "superseded") and res.image_id:
                    member_ids.append(res.image_id)
        # Preserve the archive itself (links to the same Post/Artist).
        self._capture_attachment(
-            source, post=post, artist=artist, resolved=True
+            source, post=post, artist=artist_use, resolved=True
        )
        if member_ids:
            return ImportResult(
@@ -429,7 +469,8 @@ class Importer:
        return ImportResult(status="attached")

    def _import_media(
-        self, source: Path, attribution_path: Path
+        self, source: Path, attribution_path: Path,
+        *, explicit_source: Source | None = None,
    ) -> ImportResult:
        """The media import pipeline (filters, dedup, copy, provenance).

@@ -446,7 +487,25 @@ class Importer:
        # Compute file dimensions (images only) and apply filters.
        width = height = None
        has_alpha = False
-        if not is_video(source):
+        if is_video(source):
+            # Layer-3 isolation: validate the container via ffprobe (a
+            # separate process) before the rest of the pipeline touches
+            # it. A corrupt video that would crash a decoder is rejected
+            # cleanly here, and we capture width/height for free (the
+            # importer didn't previously record video dimensions).
+            probe = safe_probe.probe_video(source)
+            if not probe.ok:
+                if probe.crashed:
+                    return ImportResult(
+                        status="failed",
+                        error=f"video probe crashed/timed out: {probe.reason}",
+                    )
+                return ImportResult(
+                    status="skipped", skip_reason=SkipReason.invalid_image,
+                    error=probe.reason,
+                )
+            width, height = probe.width, probe.height
+        else:
            try:
                with Image.open(source) as im:
                    im.verify()
@@ -558,7 +617,15 @@ class Importer:
            artist = self._attach_artist(record, artist_name)

        # Sidecar provenance (best-effort; never fails the import).
-        self._apply_sidecar(record, attribution_path, artist)
+        # explicit_source lets the FC-3c download path bind the new
+        # ImageProvenance row to its subscription Source instead of
+        # having _apply_sidecar re-derive via _lookup_source_for_sidecar.
+        # Audit 2026-06-02 — archive members extracted from a
+        # subscription-downloaded zip previously lost subscription
+        # linkage if the on-disk layout didn't match assumptions.
+        self._apply_sidecar(
+            record, attribution_path, artist, explicit_source=explicit_source,
+        )

        # Thumbnail is queued separately by the calling task; the importer
        # does not generate thumbnails inline so the import queue stays moving.
@@ -622,16 +689,36 @@ class Importer:
        them through. The sidecar JSON gallery-dl emits next to each
        downloaded file is read by `_apply_sidecar` via `find_sidecar`.

+        File-type dispatch parity with `import_one` (FC-2d-iii): zips,
+        PDFs, audio etc. become PostAttachments; archives are extracted.
+        Without this dispatch, gallery-dl-downloaded non-media bounced
+        back as `skipped+invalid_image`, which DownloadService counted
+        as an ingest error and flipped otherwise-successful runs to
+        status="error". Operator-flagged 2026-06-02 after a Lustria
+        patreon run with a 94MB OST zip went red despite 21 successful
+        image attaches.
+
        Caller's responsibilities after this returns:
          - duplicate_hash / duplicate_phash skip → delete the on-disk file
          - superseded → file stays where it is (now canonical)
          - imported → file stays where it is
+          - attached → the file's been copied into the attachments store;
+            caller may delete the on-disk original (mirrors duplicate_hash)
          - failed → file untouched; caller decides
        """
-        if not is_supported(path):
+        if path.suffix.lower() == ".json":
            return ImportResult(
                status="skipped", skip_reason=SkipReason.invalid_image,
-                error=f"unsupported extension {path.suffix}",
+                error="sidecar json is metadata, not content",
+            )
+        if is_archive(path):
+            return self._import_archive(
+                path, artist=artist, source_row=source,
+            )
+        if not is_supported(path):
+            post = self._post_for_sidecar(path, artist) if artist else None
+            return self._capture_attachment(
+                path, post=post, artist=artist, resolved=True,
            )

        # Format / dimension / transparency filters (mirror _import_media).
@@ -703,7 +790,8 @@ class Importer:
                if rel == "smaller_exists":
                    target = self.session.get(ImageRecord, match_id)
                    self._supersede(
-                        target, path, sha, phash, width, height, new_path=path
+                        target, path, sha, phash, width, height,
+                        new_path=path, artist=artist, source_row=source,
                    )
                    return ImportResult(status="superseded", image_id=match_id)

@@ -818,14 +906,15 @@ class Importer:
            src = explicit_source
        else:
            platform = sd.platform or "unknown"
-            src = self._source_for_sidecar(
+            src = self._lookup_source_for_sidecar(
                artist_id=artist.id, platform=platform,
-                artist_slug=artist.slug,
            )

        epid = sd.external_post_id or sc.stem
        post = self._find_or_create_post(
-            source_id=src.id, external_post_id=epid,
+            source_id=src.id if src else None,
+            external_post_id=epid,
+            artist_id=artist.id,
        )
        if sd.post_url is not None:
            post.post_url = sd.post_url
@@ -861,7 +950,7 @@ class Importer:
                    ImageProvenance(
                        image_record_id=record.id,
                        post_id=post.id,
-                        source_id=src.id,
+                        source_id=src.id if src else None,
                        captured_metadata=sd.raw,
                    )
                )
@@ -897,6 +986,8 @@ class Importer:
        self, existing: ImageRecord, source: Path, sha: str,
        phash: str, width: int | None, height: int | None,
        *, new_path: Path | None = None,
+        artist: Artist | None = None,
+        source_row: Source | None = None,
    ) -> None:
        """Replace `existing`'s file with the larger `source`, keeping the
        row id (so tags/series/curation stay attached). ML is cleared so
@@ -948,8 +1039,14 @@ class Importer:
        # _apply_sidecar resolves artist from the sidecar itself if the
        # existing row has none, and is internally guarded against
        # missing-or-malformed sidecars (silent return).
+        # Audit 2026-06-02: thread artist/source_row from the
+        # download-path caller (attach_in_place smaller_exists branch)
+        # so the supersede preserves explicit subscription linkage
+        # instead of re-deriving via path-walk.
        try:
-            self._apply_sidecar(existing, source, None)
+            self._apply_sidecar(
+                existing, source, artist, explicit_source=source_row,
+            )
        except Exception as exc:
            # Don't unwind the supersede DB swap if sidecar parsing
            # blows up unexpectedly — the file replacement is the
@@ -1,10 +0,0 @@
-"""FC-5 migration tooling.
-
-One module per concern (gs/ir/overlap/ml_queue/verify/cleanup).
-Each migrator returns a counts dict; the run_migration task wires
-that dict into MigrationRun.counts so the UI polling shows progress.
-
-backup + rollback were retired in FC-3h (2026-05-24); first-class
-backup lives at backend/app/services/backup_service.py and exposes
-its own /api/system/backup/* surface.
-"""
@@ -1,182 +0,0 @@
-"""Targeted cleanup migrator: delete every image attributed to one Artist.
-
-Built for the IR-migration rescue case where the filesystem scan derived
-a bogus 'imagerepo' artist from a mismatched bind-mount layout. Every
-image attributed to that artist (40k+ rows) needs to be removed — DB
-rows, original files under `/images/<bucket>/...`, and thumbnails under
-`/images/thumbs/...` — before the operator remounts and re-scans.
-
-CASCADE handles image_tag, image_provenance, series_page, and
-tag_suggestion_rejection child rows; import_task.result_image_id is
-SET NULL by FK. We also delete ImportTask rows whose source_path starts
-with the (still-existing) IR scan prefix so the next scan isn't fooled
-by them.
-"""
-from __future__ import annotations
-
-import logging
-from pathlib import Path
-
-from sqlalchemy import delete, func, select
-from sqlalchemy.ext.asyncio import AsyncSession
-
-from ...models import Artist, ImageRecord, ImportBatch, ImportTask
-
-log = logging.getLogger(__name__)
-
-_BATCH_SIZE = 500
-
-
-def _zero_counts() -> dict:
-    return {
-        "rows_processed": 0, "rows_inserted": 0, "rows_skipped": 0,
-        "files_copied": 0, "bytes_copied": 0, "conflicts": 0,
-    }
-
-
-def _thumb_path(images_root: Path, sha256_hex: str) -> tuple[Path, Path]:
-    """Return both possible thumbnail paths (.jpg and .png). We try both
-    because the extension is chosen at generate-time based on the source
-    image's mode (alpha → .png, otherwise → .jpg)."""
-    bucket = sha256_hex[:3]
-    base = images_root / "thumbs" / bucket / sha256_hex
-    return base.with_suffix(".jpg"), base.with_suffix(".png")
-
-
-def _delete_file(path: Path) -> bool:
-    """Best-effort unlink; True if the file was actually removed."""
-    try:
-        path.unlink(missing_ok=True)
-        return True
-    except OSError as exc:
-        log.warning("cleanup: failed to unlink %s: %s", path, exc)
-        return False
-
-
-async def cleanup_artist_async(
-    db: AsyncSession,
-    *,
-    slug: str,
-    images_root: Path | None = None,
-    dry_run: bool = False,
-    source_path_prefix: str | None = None,
-) -> dict:
-    """Delete every image attributed to the Artist with this slug,
-    along with the artist row itself and any associated import tasks.
-
-    Args:
-        slug: artist.slug to target (e.g. 'imagerepo').
-        images_root: defaults to /images.
-        dry_run: skip filesystem + DB writes; still walk rows for counts.
-        source_path_prefix: if set, ImportTask rows whose source_path
-            starts with this string are deleted too (use the IR scan
-            mount prefix, e.g. '/import/imagerepo').
-    """
-    root = images_root if images_root is not None else Path("/images")
-
-    artist = (await db.execute(
-        select(Artist).where(Artist.slug == slug)
-    )).scalar_one_or_none()
-    if artist is None:
-        raise ValueError(f"no Artist with slug={slug!r}")
-
-    artist_id = artist.id
-    artist_name = artist.name
-
-    total_images = (await db.execute(
-        select(func.count(ImageRecord.id)).where(ImageRecord.artist_id == artist_id)
-    )).scalar_one()
-
-    counts = _zero_counts()
-    files_deleted = 0
-    thumbs_deleted = 0
-    images_deleted = 0
-
-    # Batched delete loop. CASCADE handles image_tag, image_provenance,
-    # series_page, tag_suggestion_rejection. import_task.result_image_id
-    # is SET NULL by FK.
-    while True:
-        rows = (await db.execute(
-            select(ImageRecord.id, ImageRecord.path, ImageRecord.sha256)
-            .where(ImageRecord.artist_id == artist_id)
-            .limit(_BATCH_SIZE)
-        )).all()
-        if not rows:
-            break
-
-        ids = [r.id for r in rows]
-        counts["rows_processed"] += len(ids)
-
-        if not dry_run:
-            for r in rows:
-                if r.path:
-                    if _delete_file(Path(r.path)):
-                        files_deleted += 1
-                if r.sha256:
-                    jpg, png = _thumb_path(root, r.sha256)
-                    if _delete_file(jpg):
-                        thumbs_deleted += 1
-                    if _delete_file(png):
-                        thumbs_deleted += 1
-
-            await db.execute(
-                delete(ImageRecord).where(ImageRecord.id.in_(ids))
-            )
-            await db.commit()
-
-        images_deleted += len(ids)
-
-        if dry_run:
-            # Nothing was actually deleted from the DB; bail after one
-            # pass so we don't loop forever.
-            break
-
-    import_tasks_deleted = 0
-    if source_path_prefix and not dry_run:
-        # Delete ImportTask rows whose source_path is under the bad mount
-        # prefix. These are mostly orphaned now (result_image_id was set
-        # NULL by CASCADE) but their presence still blocks the
-        # idempotency check in scan_directory if the operator remounts
-        # the same prefix.
-        like_pattern = source_path_prefix.rstrip("/") + "/%"
-        result = await db.execute(
-            delete(ImportTask).where(ImportTask.source_path.like(like_pattern))
-        )
-        import_tasks_deleted = result.rowcount or 0
-        await db.commit()
-
-    # Sweep ImportBatch rows that are now empty.
-    empty_batches_deleted = 0
-    if not dry_run:
-        empty_batch_ids = (await db.execute(
-            select(ImportBatch.id).where(
-                ~select(ImportTask.id)
-                .where(ImportTask.batch_id == ImportBatch.id)
-                .exists()
-            )
-        )).scalars().all()
-        if empty_batch_ids:
-            result = await db.execute(
-                delete(ImportBatch).where(ImportBatch.id.in_(empty_batch_ids))
-            )
-            empty_batches_deleted = result.rowcount or 0
-            await db.commit()
-
-    # Finally, the artist row.
-    if not dry_run:
-        await db.execute(delete(Artist).where(Artist.id == artist_id))
-        await db.commit()
-
-    return {
-        "counts": counts,
-        "artist": {"id": artist_id, "name": artist_name, "slug": slug},
-        "summary": {
-            "images_targeted": total_images,
-            "images_deleted": images_deleted,
-            "files_deleted": files_deleted,
-            "thumbs_deleted": thumbs_deleted,
-            "import_tasks_deleted": import_tasks_deleted,
-            "empty_batches_deleted": empty_batches_deleted,
-            "dry_run": dry_run,
-        },
-    }
@@ -1,126 +0,0 @@
-"""GallerySubscriber export → FabledCurator ingest.
-
-Reads a parsed gallerysubscriber-export-v1.json dict (no DB connection
-to GS). Creates Artist (from subscriptions) + Source (nested under each
-subscription) + Credential (re-encrypted with FC's key). Idempotent on
-natural keys: Artist.slug, (artist_id, platform, url), Credential.platform.
-
-Credentials arrive plaintext in the export — GS's export script
-decrypts using GS's Fernet key in GS's own process. FC re-encrypts
-with FC's CredentialCrypto.
-"""
-from __future__ import annotations
-
-import json
-
-from sqlalchemy import select
-from sqlalchemy.ext.asyncio import AsyncSession
-
-from ...models import Artist, Credential, Source
-from ...utils.slug import slugify
-from ..credential_crypto import CredentialCrypto
-
-
-def _zero_counts() -> dict:
-    return {
-        "rows_processed": 0, "rows_inserted": 0, "rows_skipped": 0,
-        "files_copied": 0, "bytes_copied": 0, "conflicts": 0,
-    }
-
-
-async def migrate_async(
-    db: AsyncSession,
-    *,
-    data: dict,
-    fc_crypto: CredentialCrypto | None = None,
-    dry_run: bool = False,
-) -> dict:
-    """Ingest a parsed gallerysubscriber-export-v1.json dict."""
-    if data.get("source_app") != "gallerysubscriber":
-        raise ValueError("export source_app must be 'gallerysubscriber'")
-    if data.get("schema_version") != 1:
-        raise ValueError(f"unsupported schema_version: {data.get('schema_version')}")
-
-    counts = _zero_counts()
-
-    # Phase 1: subscriptions → Artist; nested sources within each.
-    for sub in data.get("subscriptions", []):
-        counts["rows_processed"] += 1
-        slug = slugify(sub["name"])
-        artist = (await db.execute(
-            select(Artist).where(Artist.slug == slug)
-        )).scalar_one_or_none()
-        if artist is None:
-            if dry_run:
-                counts["rows_inserted"] += 1
-                # Continue to nested sources, but they can't link without an artist row.
-                continue
-            notes = json.dumps(sub.get("metadata"), indent=2) if sub.get("metadata") else None
-            artist = Artist(
-                name=sub["name"], slug=slug,
-                is_subscription=True,
-                auto_check=bool(sub.get("enabled", True)),
-                notes=notes,
-            )
-            db.add(artist)
-            await db.flush()
-            counts["rows_inserted"] += 1
-        else:
-            counts["rows_skipped"] += 1
-
-        # Nested sources under this subscription.
-        for src in sub.get("sources", []):
-            counts["rows_processed"] += 1
-            existing = (await db.execute(
-                select(Source).where(
-                    Source.artist_id == artist.id,
-                    Source.platform == src["platform"],
-                    Source.url == src["url"],
-                )
-            )).scalar_one_or_none()
-            if existing is not None:
-                counts["rows_skipped"] += 1
-                continue
-            if dry_run:
-                counts["rows_inserted"] += 1
-                continue
-            db.add(Source(
-                artist_id=artist.id,
-                platform=src["platform"],
-                url=src["url"],
-                enabled=bool(src.get("enabled", True)),
-                check_interval_override=src.get("check_interval"),
-                config_overrides=src.get("metadata") or {},
-            ))
-            counts["rows_inserted"] += 1
-
-    # Phase 2: credentials.
-    for cred in data.get("credentials", []):
-        counts["rows_processed"] += 1
-        existing = (await db.execute(
-            select(Credential).where(Credential.platform == cred["platform"])
-        )).scalar_one_or_none()
-        if existing is not None:
-            counts["rows_skipped"] += 1
-            continue
-        if dry_run:
-            counts["rows_inserted"] += 1
-            continue
-        if fc_crypto is None:
-            # Without a crypto helper we can't encrypt — skip rather than
-            # store plaintext.
-            counts["rows_skipped"] += 1
-            counts["conflicts"] += 1
-            continue
-        encrypted = fc_crypto.encrypt(cred["plaintext"])
-        db.add(Credential(
-            platform=cred["platform"],
-            credential_type=cred.get("credential_type") or "cookies",
-            encrypted_blob=encrypted,
-            expires_at=cred.get("expires_at"),
-        ))
-        counts["rows_inserted"] += 1
-
-    if not dry_run:
-        await db.commit()
-    return counts
@@ -1,146 +0,0 @@
-"""ImageRepo export → FabledCurator ingest.
-
-Reads a parsed imagerepo-export-v1.json dict (no DB connection to IR).
-Creates Tag rows (skipping artist/post kinds, resolving fandom_name to
-FK). Writes the per-image-sha256 artist assignments + tag associations
-+ series page assignments to /images/_migration_state/ir_tag_manifest.json
-so tag_apply.py can join them to ImageRecord rows AFTER the operator
-runs FC's filesystem scan.
-"""
-from __future__ import annotations
-
-import json
-from pathlib import Path
-
-from sqlalchemy import select
-from sqlalchemy.ext.asyncio import AsyncSession
-
-from ...models import Tag, TagKind
-
-_SKIP_KINDS = frozenset({"artist", "post"})
-_MIGRATION_STATE_DIRNAME = "_migration_state"
-_IR_MANIFEST_FILENAME = "ir_tag_manifest.json"
-
-
-def _zero_counts() -> dict:
-    return {
-        "rows_processed": 0, "rows_inserted": 0, "rows_skipped": 0,
-        "files_copied": 0, "bytes_copied": 0, "conflicts": 0,
-    }
-
-
-def manifest_path(images_root: Path | None = None) -> Path:
-    root = images_root if images_root is not None else Path("/images")
-    p = root / _MIGRATION_STATE_DIRNAME
-    p.mkdir(parents=True, exist_ok=True)
-    return p / _IR_MANIFEST_FILENAME
-
-
-async def _resolve_fandom_id(
-    db: AsyncSession, fandom_name: str | None, dry_run: bool,
-) -> int | None:
-    """Find-or-create a fandom-kind Tag by name."""
-    if not fandom_name:
-        return None
-    existing = (await db.execute(
-        select(Tag).where(Tag.name == fandom_name, Tag.kind == "fandom")
-    )).scalar_one_or_none()
-    if existing is not None:
-        return existing.id
-    if dry_run:
-        return None
-    t = Tag(name=fandom_name, kind=TagKind.fandom)
-    db.add(t)
-    await db.flush()
-    return t.id
-
-
-async def migrate_async(
-    db: AsyncSession,
-    *,
-    data: dict,
-    images_root: Path | None = None,
-    dry_run: bool = False,
-) -> dict:
-    """Ingest a parsed imagerepo-export-v1.json dict.
-
-    Creates Tag rows + writes the IR tag manifest file. Tag-to-image
-    binding happens later in tag_apply.py (after FC's filesystem scan
-    populates image_record.sha256 → id).
-    """
-    if data.get("source_app") != "imagerepo":
-        raise ValueError("export source_app must be 'imagerepo'")
-    if data.get("schema_version") not in (1, 2):
-        raise ValueError(f"unsupported schema_version: {data.get('schema_version')}")
-
-    counts = _zero_counts()
-
-    # Phase 1: tags (skip artist + post kinds; resolve fandom_name → fandom_id).
-    # First pass: create all fandom-kind tags so they're available for FK resolution.
-    for tag in data.get("tags", []):
-        kind = tag.get("kind") or "general"
-        if kind != "fandom":
-            continue
-        counts["rows_processed"] += 1
-        existing = (await db.execute(
-            select(Tag).where(Tag.name == tag["name"], Tag.kind == "fandom")
-        )).scalar_one_or_none()
-        if existing is not None:
-            counts["rows_skipped"] += 1
-            continue
-        if dry_run:
-            counts["rows_inserted"] += 1
-            continue
-        db.add(Tag(name=tag["name"], kind=TagKind.fandom))
-        counts["rows_inserted"] += 1
-    if not dry_run:
-        await db.flush()
-
-    # Second pass: every other kind.
-    for tag in data.get("tags", []):
-        kind_str = tag.get("kind") or "general"
-        if kind_str in _SKIP_KINDS:
-            counts["rows_skipped"] += 1
-            continue
-        if kind_str == "fandom":
-            continue  # handled above
-        counts["rows_processed"] += 1
-        try:
-            kind = TagKind(kind_str)
-        except ValueError:
-            kind = TagKind.general
-        fandom_id = await _resolve_fandom_id(db, tag.get("fandom_name"), dry_run)
-        existing = (await db.execute(
-            select(Tag).where(Tag.name == tag["name"], Tag.kind == kind)
-        )).scalar_one_or_none()
-        if existing is not None:
-            counts["rows_skipped"] += 1
-            continue
-        if dry_run:
-            counts["rows_inserted"] += 1
-            continue
-        db.add(Tag(name=tag["name"], kind=kind, fandom_id=fandom_id))
-        counts["rows_inserted"] += 1
-
-    if not dry_run:
-        await db.commit()
-
-    # Phase 2: write the per-image manifest for tag_apply.py to consume later.
-    # schema_version 2 (added 2026-05-24) carries `image_posts` for
-    # Post + Source + ImageProvenance restore; schema 1 manifests
-    # without it stay valid (tag_apply treats the missing field as []).
-    manifest = {
-        "schema_version": data.get("schema_version", 1),
-        "image_artist_assignments": data.get("image_artist_assignments", []),
-        "image_tag_associations": data.get("image_tag_associations", []),
-        "series_pages": data.get("series_pages", []),
-        "image_posts": data.get("image_posts", []),
-    }
-    counts["rows_processed"] += len(manifest["image_artist_assignments"])
-    counts["rows_processed"] += len(manifest["image_tag_associations"])
-    counts["rows_processed"] += len(manifest["series_pages"])
-    counts["rows_processed"] += len(manifest["image_posts"])
-    if not dry_run:
-        manifest_path(images_root).write_text(json.dumps(manifest, indent=2))
-
-    return counts
@@ -1,21 +0,0 @@
-"""Queue every migrated image_record with no embedding for ML re-processing."""
-from __future__ import annotations
-
-from sqlalchemy import select
-from sqlalchemy.ext.asyncio import AsyncSession
-
-from ...models import ImageRecord
-
-
-async def queue_all_unprocessed_async(db: AsyncSession) -> int:
-    """Find every ImageRecord with siglip_embedding IS NULL, fire
-    tag_and_embed.delay(id) for each. Returns count queued.
-    """
-    from ...tasks.ml import tag_and_embed
-
-    rows = (await db.execute(
-        select(ImageRecord.id).where(ImageRecord.siglip_embedding.is_(None))
-    )).scalars().all()
-    for image_id in rows:
-        tag_and_embed.delay(image_id)
-    return len(rows)
@@ -1,368 +0,0 @@
-"""Apply the IR tag manifest after FC's filesystem scan.
-
-Reads /images/_migration_state/ir_tag_manifest.json and joins each entry
-to an ImageRecord row by sha256 (which exists after the operator runs
-FC's filesystem scan over the mounted IR images dir).
-
- image_artist_assignments → ImageRecord.artist_id (find_or_create Artist by slug).
- image_tag_associations  → image_tag insert (idempotent).
- series_pages            → series_page insert (idempotent on image_id unique).
- image_posts (schema v2) → Source + Post + ImageProvenance restore.
-
-Unmatched sha256s are logged into the result's `unmatched` list so the
-Celery task can drop them into MigrationRun.metadata for the operator
-to inspect.
-"""
-from __future__ import annotations
-
-import json
-from datetime import datetime
-from pathlib import Path
-
-from sqlalchemy import select
-from sqlalchemy.ext.asyncio import AsyncSession
-
-from ...models import (
-    Artist,
-    ImageProvenance,
-    ImageRecord,
-    Post,
-    SeriesPage,
-    Source,
-    Tag,
-    TagKind,
-    image_tag,
-)
-from ...utils.slug import slugify
-from .ir_ingest import manifest_path
-
-# Per-platform artist-profile URL — used as Source.url when restoring
-# IR PostMetadata into FC. Must cover every platform that
-# backend/app/services/extension_service.py:_PLATFORM_PATTERNS
-# recognizes; an entry missing here silently drops ALL PostMetadata for
-# that platform during phase 4 (operator hit this 2026-05-25:
-# DeviantArt + Pixiv posts in the IR migration produced empty
-# ImageProvenance because they fell through this table).
-#
-# Pixiv caveat: the real profile URL takes a numeric user_id
-# (https://www.pixiv.net/users/12345), but IR's PostMetadata.artist
-# stores the display name not the id. We use the slugified name here
-# so we preserve the artist→post→image linkage; the resulting Source.url
-# won't resolve in a browser and the operator may want to manually fix
-# it via Settings → Subscriptions once the migration lands.
-_PLATFORM_PROFILE_URL = {
-    "patreon":       "https://www.patreon.com/{slug}",
-    "subscribestar": "https://www.subscribestar.com/{slug}",
-    "hentaifoundry": "https://www.hentai-foundry.com/user/{slug}",
-    "deviantart":    "https://www.deviantart.com/{slug}",
-    "pixiv":         "https://www.pixiv.net/users/{slug}",
-}
-
-
-def _profile_url(platform: str, artist_slug: str) -> str | None:
-    fmt = _PLATFORM_PROFILE_URL.get(platform)
-    return fmt.format(slug=artist_slug) if fmt else None
-
-
-async def _find_or_create_source(
-    db: AsyncSession, *, artist_id: int, platform: str, url: str, dry_run: bool,
-) -> int | None:
-    existing = (await db.execute(
-        select(Source.id).where(
-            Source.artist_id == artist_id,
-            Source.platform == platform,
-            Source.url == url,
-        )
-    )).scalar_one_or_none()
-    if existing is not None:
-        return existing
-    if dry_run:
-        return None
-    s = Source(artist_id=artist_id, platform=platform, url=url, enabled=False)
-    db.add(s)
-    await db.flush()
-    return s.id
-
-
-async def _find_or_create_post(
-    db: AsyncSession, *,
-    source_id: int, external_post_id: str,
-    title: str | None, description: str | None, post_url: str | None,
-    post_date_iso: str | None, attachment_count: int, dry_run: bool,
-) -> int | None:
-    existing = (await db.execute(
-        select(Post.id).where(
-            Post.source_id == source_id,
-            Post.external_post_id == external_post_id,
-        )
-    )).scalar_one_or_none()
-    if existing is not None:
-        return existing
-    if dry_run:
-        return None
-    post_date = None
-    if post_date_iso:
-        post_date = datetime.fromisoformat(post_date_iso)
-    p = Post(
-        source_id=source_id,
-        external_post_id=external_post_id,
-        post_title=title,
-        description=description,
-        post_url=post_url,
-        post_date=post_date,
-        attachment_count=attachment_count,
-        raw_metadata={"migrated_from": "imagerepo"},
-    )
-    db.add(p)
-    await db.flush()
-    return p.id
-
-
-async def _ensure_provenance(
-    db: AsyncSession, *,
-    image_id: int, post_id: int, source_id: int, dry_run: bool,
-) -> bool:
-    """Returns True if a new ImageProvenance row was inserted.
-
-    Also sets ImageRecord.primary_post_id to this post if the image
-    doesn't already have one — preserves any primary_post_id already
-    assigned at download time by the importer (don't clobber). This is
-    the linkage gallery_service.py uses to surface Post.post_date as
-    the image's effective date for sort/group/jump/neighbor nav.
-    """
-    existing = (await db.execute(
-        select(ImageProvenance.id).where(
-            ImageProvenance.image_record_id == image_id,
-            ImageProvenance.post_id == post_id,
-            ImageProvenance.source_id == source_id,
-        )
-    )).scalar_one_or_none()
-
-    # Whether-or-not the provenance row already exists, ensure the
-    # image's primary_post_id is set so the gallery date-coalesce works.
-    # Idempotent: only writes when currently NULL.
-    if not dry_run:
-        await db.execute(
-            ImageRecord.__table__.update()
-            .where(ImageRecord.id == image_id)
-            .where(ImageRecord.primary_post_id.is_(None))
-            .values(primary_post_id=post_id)
-        )
-
-    if existing is not None:
-        return False
-    if dry_run:
-        return True
-    db.add(ImageProvenance(
-        image_record_id=image_id, post_id=post_id, source_id=source_id,
-    ))
-    await db.flush()
-    return True
-
-
-def _zero_counts() -> dict:
-    return {
-        "rows_processed": 0, "rows_inserted": 0, "rows_skipped": 0,
-        "files_copied": 0, "bytes_copied": 0, "conflicts": 0,
-    }
-
-
-async def _ensure_artist_id(
-    db: AsyncSession, artist_name: str, dry_run: bool,
-) -> int | None:
-    if not artist_name or not artist_name.strip():
-        return None
-    slug = slugify(artist_name)
-    existing = (await db.execute(
-        select(Artist).where(Artist.slug == slug)
-    )).scalar_one_or_none()
-    if existing is not None:
-        return existing.id
-    if dry_run:
-        return None
-    a = Artist(name=artist_name, slug=slug, is_subscription=False)
-    db.add(a)
-    await db.flush()
-    return a.id
-
-
-async def _resolve_tag_id(
-    db: AsyncSession, tag_name: str, tag_kind: str,
-) -> int | None:
-    try:
-        kind = TagKind(tag_kind)
-    except ValueError:
-        kind = TagKind.general
-    row = (await db.execute(
-        select(Tag.id).where(Tag.name == tag_name, Tag.kind == kind)
-    )).scalar_one_or_none()
-    return row
-
-
-async def _sha_to_image_id(db: AsyncSession, sha: str) -> int | None:
-    return (await db.execute(
-        select(ImageRecord.id).where(ImageRecord.sha256 == sha)
-    )).scalar_one_or_none()
-
-
-async def apply_async(
-    db: AsyncSession,
-    *,
-    images_root: Path | None = None,
-    dry_run: bool = False,
-) -> dict:
-    """Apply the manifest. Returns counts + an `unmatched` list of sha256s."""
-    mf_path = manifest_path(images_root)
-    if not mf_path.exists():
-        raise FileNotFoundError(f"no IR tag manifest at {mf_path}")
-
-    manifest = json.loads(mf_path.read_text())
-    counts = _zero_counts()
-    unmatched: list[dict] = []
-
-    # 1. Artist assignments.
-    for entry in manifest.get("image_artist_assignments", []):
-        counts["rows_processed"] += 1
-        img_id = await _sha_to_image_id(db, entry["sha256"])
-        if img_id is None:
-            unmatched.append({"kind": "artist", **entry})
-            counts["rows_skipped"] += 1
-            continue
-        aid = await _ensure_artist_id(db, entry["artist_name"], dry_run)
-        if aid is None:
-            counts["rows_skipped"] += 1
-            continue
-        if dry_run:
-            counts["rows_inserted"] += 1
-            continue
-        img = await db.get(ImageRecord, img_id)
-        if img is not None and img.artist_id != aid:
-            img.artist_id = aid
-            counts["rows_inserted"] += 1
-        else:
-            counts["rows_skipped"] += 1
-
-    # 2. Tag associations.
-    for entry in manifest.get("image_tag_associations", []):
-        counts["rows_processed"] += 1
-        img_id = await _sha_to_image_id(db, entry["sha256"])
-        if img_id is None:
-            unmatched.append({"kind": "tag", **entry})
-            counts["rows_skipped"] += 1
-            continue
-        tag_id = await _resolve_tag_id(
-            db, entry["tag_name"], entry.get("tag_kind") or "general",
-        )
-        if tag_id is None:
-            counts["rows_skipped"] += 1
-            continue
-        # Skip if association already exists.
-        already = (await db.execute(
-            select(image_tag.c.image_record_id).where(
-                image_tag.c.image_record_id == img_id,
-                image_tag.c.tag_id == tag_id,
-            )
-        )).first()
-        if already is not None:
-            counts["rows_skipped"] += 1
-            continue
-        if dry_run:
-            counts["rows_inserted"] += 1
-            continue
-        await db.execute(image_tag.insert().values(
-            image_record_id=img_id, tag_id=tag_id, source="manual",
-        ))
-        counts["rows_inserted"] += 1
-
-    # 3. Series pages.
-    for entry in manifest.get("series_pages", []):
-        counts["rows_processed"] += 1
-        img_id = await _sha_to_image_id(db, entry["sha256"])
-        if img_id is None:
-            unmatched.append({"kind": "series", **entry})
-            counts["rows_skipped"] += 1
-            continue
-        series_tag_id = await _resolve_tag_id(db, entry["series_tag_name"], "series")
-        if series_tag_id is None:
-            counts["rows_skipped"] += 1
-            continue
-        existing = (await db.execute(
-            select(SeriesPage).where(SeriesPage.image_id == img_id)
-        )).scalar_one_or_none()
-        if existing is not None:
-            counts["rows_skipped"] += 1
-            continue
-        if dry_run:
-            counts["rows_inserted"] += 1
-            continue
-        db.add(SeriesPage(
-            series_tag_id=series_tag_id,
-            image_id=img_id,
-            page_number=entry["page_number"],
-        ))
-        counts["rows_inserted"] += 1
-
-    # 4. Image posts (schema v2) → Source + Post + ImageProvenance.
-    # Restores IR PostMetadata as FC's downloader-track provenance,
-    # so the modal's ProvenancePanel surfaces title/description/
-    # source URL/publish date the same way it does for live
-    # gallery-dl downloads.
-    for entry in manifest.get("image_posts", []):
-        counts["rows_processed"] += 1
-        platform = entry.get("platform")
-        artist_name = entry.get("artist")
-        if not platform or not artist_name:
-            counts["rows_skipped"] += 1
-            continue
-
-        aid = await _ensure_artist_id(db, artist_name, dry_run)
-        if aid is None:
-            counts["rows_skipped"] += 1
-            continue
-
-        url = _profile_url(platform, slugify(artist_name))
-        if url is None:
-            counts["rows_skipped"] += 1
-            continue
-
-        source_id = await _find_or_create_source(
-            db, artist_id=aid, platform=platform, url=url, dry_run=dry_run,
-        )
-        if source_id is None:
-            counts["rows_skipped"] += 1
-            continue
-
-        post_id = await _find_or_create_post(
-            db, source_id=source_id,
-            external_post_id=entry.get("post_id") or "",
-            title=entry.get("title"),
-            description=entry.get("description"),
-            post_url=entry.get("source_url"),
-            post_date_iso=entry.get("published_at"),
-            attachment_count=entry.get("attachment_count") or 0,
-            dry_run=dry_run,
-        )
-        if post_id is None:
-            counts["rows_skipped"] += 1
-            continue
-
-        for sha in entry.get("image_sha256s", []):
-            img_id = await _sha_to_image_id(db, sha)
-            if img_id is None:
-                unmatched.append({
-                    "kind": "post", "sha256": sha,
-                    "post_id": entry.get("post_id"),
-                })
-                continue
-            inserted = await _ensure_provenance(
-                db, image_id=img_id, post_id=post_id,
-                source_id=source_id, dry_run=dry_run,
-            )
-            if inserted:
-                counts["rows_inserted"] += 1
-            else:
-                counts["rows_skipped"] += 1
-
-    if not dry_run:
-        await db.commit()
-    return {"counts": counts, "unmatched": unmatched}
@@ -1,80 +0,0 @@
-"""Post-migration verification: row counts + sha256 sampling."""
-from __future__ import annotations
-
-import hashlib
-from pathlib import Path
-
-from sqlalchemy import func, select
-from sqlalchemy.ext.asyncio import AsyncSession
-
-from ...models import Artist, Credential, ImageRecord, Source, Tag
-
-
-async def verify_async(db: AsyncSession, *, expected: dict | None = None) -> dict:
-    """Return per-check status dicts. `expected` is optional row-count
-    assertions; checks default to status='ok' when no expected provided."""
-    expected = expected or {}
-    results: dict[str, dict] = {}
-
-    checks = {
-        "artist_subscriptions": (
-            select(func.count(Artist.id)).where(Artist.is_subscription.is_(True))
-        ),
-        "source_count": select(func.count(Source.id)),
-        "credential_count": select(func.count(Credential.id)),
-        "tag_count": select(func.count(Tag.id)),
-        "image_record_imported_or_downloaded": (
-            select(func.count(ImageRecord.id))
-            .where(ImageRecord.origin.in_(["imported_filesystem", "downloaded"]))
-        ),
-    }
-    for name, stmt in checks.items():
-        actual = (await db.execute(stmt)).scalar_one()
-        exp = expected.get(name)
-        status = "ok" if exp is None or exp == actual else "mismatch"
-        results[name] = {"status": status, "actual": int(actual), "expected": exp}
-    return results
-
-
-async def verify_sha256_sample(
-    db: AsyncSession, *, sample_size: int = 20,
-) -> dict:
-    """Sample N image_records; verify file exists + sha256 matches."""
-    rows = (await db.execute(
-        select(ImageRecord.id, ImageRecord.path, ImageRecord.sha256)
-        .order_by(func.random()).limit(sample_size)
-    )).all()
-
-    matched = 0
-    mismatched = 0
-    missing = 0
-    samples: list[dict] = []
-    for img_id, path, expected_sha in rows:
-        p = Path(path)
-        # Sync stdlib filesystem ops are intentional: this verify pass runs
-        # inside a Celery task under asyncio.run; no other awaitables compete
-        # for the loop. Same pattern as download_service.py.
-        if not p.exists():  # noqa: ASYNC240
-            missing += 1
-            samples.append({"id": img_id, "path": path, "result": "missing"})
-            continue
-        h = hashlib.sha256()
-        with p.open("rb") as f:  # noqa: ASYNC230
-            for chunk in iter(lambda: f.read(65536), b""):
-                h.update(chunk)
-        if h.hexdigest() == expected_sha:
-            matched += 1
-            samples.append({"id": img_id, "result": "ok"})
-        else:
-            mismatched += 1
-            samples.append({
-                "id": img_id, "path": path, "result": "mismatch",
-                "expected_sha": expected_sha, "actual_sha": h.hexdigest(),
-            })
-    return {
-        "sample_size": len(rows),
-        "matched": matched,
-        "mismatched": mismatched,
-        "missing": missing,
-        "samples": samples,
-    }
@@ -19,7 +19,6 @@ from ...models import (
    TagReferenceEmbedding,
 )
 from ...models.tag import image_tag
-from .embedder import MODEL_VERSION as SIGLIP_VERSION

 ELIGIBLE_KINDS = {
    TagKind.character,
@@ -46,6 +45,21 @@ class CentroidService:
            )
        ).scalar_one()

+    async def _model_version(self) -> str:
+        """Audit 2026-06-02: SigLIP model-version stamp comes from the
+        DB row, not the env constant. tag_and_embed (tasks/ml.py:110)
+        already reads from MLSettings.embedder_model_version, so by
+        sourcing centroid stamps + drift checks from the same row, we
+        eliminate the silent-drift case the audit flagged. env
+        SIGLIP_MODEL_VERSION still drives which model embedder.py
+        loads at runtime; the version stamp is purely the operator-
+        controlled identifier."""
+        return (
+            await self.session.execute(
+                select(MLSettings.embedder_model_version).where(MLSettings.id == 1)
+            )
+        ).scalar_one()
+
    async def recompute_for_tag(self, tag_id: int) -> bool:
        """Recompute one tag's centroid. Returns True if a centroid was
        written, False if skipped (ineligible kind or too few members)."""
@@ -69,19 +83,20 @@ class CentroidService:
            return False

        centroid = np.mean(np.stack(embeddings), axis=0).astype(np.float32)
+        model_version = await self._model_version()

        stmt = insert(TagReferenceEmbedding).values(
            tag_id=tag_id,
            embedding=centroid.tolist(),
            reference_count=len(embeddings),
-            model_version=SIGLIP_VERSION,
+            model_version=model_version,
        )
        stmt = stmt.on_conflict_do_update(
            index_elements=["tag_id"],
            set_={
                "embedding": centroid.tolist(),
                "reference_count": len(embeddings),
-                "model_version": SIGLIP_VERSION,
+                "model_version": model_version,
                "updated_at": func.now(),
            },
        )
@@ -92,6 +107,7 @@ class CentroidService:
        """Tag ids whose centroid is stale: member count != reference_count,
        OR no centroid row, OR centroid built on a different SigLIP version.
        Only considers eligible-kind tags with embeddings present."""
+        current_model_version = await self._model_version()
        member_counts = (
            select(
                image_tag.c.tag_id.label("tag_id"),
@@ -116,7 +132,7 @@ class CentroidService:
                    TagReferenceEmbedding.reference_count
                    != member_counts.c.members
                )
-                | (TagReferenceEmbedding.model_version != SIGLIP_VERSION)
+                | (TagReferenceEmbedding.model_version != current_model_version)
            )
        )
        return list((await self.session.execute(stmt)).scalars().all())
@@ -4,7 +4,7 @@ threshold-filtered, category-grouped, ranked suggestions for one image.

 from dataclasses import dataclass, field

-from sqlalchemy import select
+from sqlalchemy import func, select
 from sqlalchemy.ext.asyncio import AsyncSession

 from ...models import (
@@ -16,6 +16,7 @@ from ...models import (
 from ...models.tag import image_tag
 from .aliases import AliasService
 from .centroids import CentroidService
+from .tag_name import normalize as normalize_tag_name
 from .tagger import SURFACED_CATEGORIES


@@ -48,11 +49,11 @@ class SuggestionService:
        ).scalar_one()

    def _threshold_for(self, s: MLSettings, category: str) -> float:
-        # 'artist' intentionally absent (FC-2d-vii-c) — falls through to
-        # the 1.01 "never surfaces" default like any unsurfaced category.
+        # 'artist' (FC-2d-vii-c) and 'copyright' (2026-06-01) retired;
+        # both fall through to the 1.01 "never surfaces" default like any
+        # unsurfaced category.
        return {
            "character": s.suggestion_threshold_character,
-            "copyright": s.suggestion_threshold_copyright,
            "general": s.suggestion_threshold_general,
        }.get(category, 1.01)

@@ -84,7 +85,12 @@ class SuggestionService:
        )

        # --- Camie predictions ---
-        candidates: list[tuple[str, str, float]] = []
+        # candidates carry (raw_name, display_name, category, confidence).
+        # raw_name = the booru-formatted vocab key, kept for alias_map
+        # lookup since alias rows are hand-curated against raw keys.
+        # display_name = normalize_tag_name(raw_name) — what the operator
+        # sees AND what gets written to tag.name on Accept.
+        candidates: list[tuple[str, str, str, float]] = []
        for name, p in predictions.items():
            category = p.get("category", "general")
            if category not in SURFACED_CATEGORIES:
@@ -92,10 +98,14 @@ class SuggestionService:
            conf = float(p.get("confidence", 0.0))
            if conf < self._threshold_for(settings, category):
                continue
-            candidates.append((name, category, conf))
+            display = normalize_tag_name(name)
+            if display is None:
+                # emoticon / pure-punctuation vocab entry — drop entirely
+                continue
+            candidates.append((name, display, category, conf))

        alias_map = await self.aliases.resolve_many(
-            [(n, c) for n, c, _ in candidates]
+            [(raw, c) for raw, _disp, c, _conf in candidates]
        )

        merged: dict[object, Suggestion] = {}
@@ -116,8 +126,8 @@ class SuggestionService:
                    creates_new_tag=existing.creates_new_tag,
                )

-        for name, category, conf in candidates:
-            canonical = alias_map.get((name, category))
+        for raw, display, category, conf in candidates:
+            canonical = alias_map.get((raw, category))
            if canonical is not None:
                if canonical.id in applied or canonical.id in rejected:
                    continue
@@ -133,9 +143,17 @@ class SuggestionService:
                    ),
                )
            else:
+                # Case-insensitive match on BOTH the raw camie key AND
+                # the normalized form — covers legacy underscore-named
+                # Tag rows accepted before normalization shipped, AND
+                # any tag the operator created with the human form.
                existing_tag = (
                    await self.session.execute(
-                        select(Tag).where(Tag.name == name)
+                        select(Tag).where(
+                            func.lower(Tag.name).in_(
+                                [raw.lower(), display.lower()]
+                            )
+                        )
                    )
                ).scalars().first()
                if existing_tag is not None:
@@ -157,10 +175,10 @@ class SuggestionService:
                    )
                else:
                    _merge(
-                        f"raw:{name}:{category}",
+                        f"raw:{display}:{category}",
                        Suggestion(
                            canonical_tag_id=None,
-                            display_name=name,
+                            display_name=display,
                            category=category,
                            score=conf,
                            source="tagger",
@@ -0,0 +1,62 @@
+"""Camie vocabulary -> human-readable tag-name normalization.
+
+Camie v2's ~57k tag vocabulary is booru-derived and arrives as raw
+strings like `uchiha_sasuke_(naruto)`, `#unicus_(idolmaster)`,
+`1000-nen_ikiteru_(vocaloid)`, or `:/`. We want the operator to see
+"Uchiha Sasuke", "Unicus", "1000-Nen Ikiteru", or to never see the
+emoticon at all — and we want the same clean string to be what lands
+in `tag.name` when the suggestion is accepted, so Accept matches the
+existing-tag convention (`tag_service.find_or_create`).
+
+Rules (operator-approved 2026-06-03):
+  1. Strip leading junk chars (#, ., +, ;, ~, _, whitespace)
+  2. Drop trailing `_(disambiguator)` block(s), iteratively
+  3. Strip wrapping single/double quotes (after disambig removal so
+     `"foo_em_up"_(series)` -> `"foo_em_up"` -> `foo_em_up`)
+  4. Replace remaining `_` with space; collapse runs of whitespace
+  5. Add a space after any `:` (namespace:tag -> namespace: tag)
+  6. Preserve hyphens (booru hyphens often carry meaning)
+  7. Title-case each space-separated word (first character only —
+     apostrophes, digits, hyphens stay)
+  8. If no letters AND no digits remain, return None (drops emoticons
+     like `:/` or `^_^`; preserves bare digit tags like `2005`)
+  9. No surname/givenname swap — no reliable signal in the vocab
+"""
+
+import re
+
+_LEADING_JUNK = re.compile(r"^[#.+;~_\s]+")
+_TRAILING_DISAMBIG = re.compile(r"_\([^)]*\)\s*$")
+_MULTISPACE = re.compile(r"\s+")
+_COLON_NOSPACE = re.compile(r":(?=\S)")
+_HAS_ALPHANUMERIC = re.compile(r"[A-Za-z0-9]")
+
+
+def _strip_wrapping_quotes(s: str) -> str:
+    if len(s) >= 2 and s[0] == s[-1] and s[0] in ('"', "'"):
+        return s[1:-1]
+    return s
+
+
+def _title_word(w: str) -> str:
+    return w[:1].upper() + w[1:] if w else w
+
+
+def normalize(raw: str) -> str | None:
+    """Return the human-readable form of a raw Camie tag, or None if the
+    string is junk (emoticon, empty after stripping)."""
+    if not raw:
+        return None
+    s = _LEADING_JUNK.sub("", raw)
+    while True:
+        new = _TRAILING_DISAMBIG.sub("", s)
+        if new == s:
+            break
+        s = new
+    s = _strip_wrapping_quotes(s)
+    s = s.replace("_", " ")
+    s = _COLON_NOSPACE.sub(": ", s)
+    s = _MULTISPACE.sub(" ", s).strip()
+    if not s or not _HAS_ALPHANUMERIC.search(s):
+        return None
+    return " ".join(_title_word(w) for w in s.split(" "))
@@ -38,10 +38,13 @@ STORE_FLOOR = float(os.environ.get("TAGGER_STORE_FLOOR", "0.05"))

 # The categories FC-2b surfaces in the UI. Others (meta/rating/year) are
 # still stored but the suggestion service filters them out.
-# FC-2d-vii-c: 'artist' retired — artist identity is acquisition-derived
-# (image_record.artist_id), never ML-inferred. Raw predictions are still
-# stored at STORE_FLOOR but artist never surfaces.
-SURFACED_CATEGORIES = {"character", "copyright", "general"}
+# 'artist' retired in FC-2d-vii-c — artist identity is acquisition-derived
+# (image_record.artist_id), never ML-inferred. 'copyright' retired
+# 2026-06-01 — operator doesn't use the copyright tag-kind; fandom is
+# this app's franchise/series concept (per TagsView.vue's doc comment).
+# Raw predictions for both categories still get stored at STORE_FLOOR but
+# don't surface in suggestions.
+SURFACED_CATEGORIES = {"character", "general"}

 # ImageNet preprocessing constants (per Camie v2 onnx_inference.py).
 _IMAGENET_MEAN = np.array([0.485, 0.456, 0.406], dtype=np.float32)
@@ -1,140 +0,0 @@
-"""FC-3b platforms registry — the single source of truth for what
-FabledCurator supports.
-
-Lifted from GallerySubscriber's
-~/Nextcloud/Projects/GallerySubscriber/backend/app/api/platforms.py
-and ~/.../extension/lib/platforms.js. Six platforms; auth_type and
-URL patterns match GS exactly so the existing browser extension
-hits FC unmodified.
-"""
-
-from dataclasses import dataclass
-from typing import Literal
-
-
-@dataclass(frozen=True)
-class PlatformInfo:
-    key: str
-    name: str
-    description: str
-    auth_type: Literal["cookies", "token"]
-    requires_auth: bool
-    url_pattern: str
-    url_examples: list[str]
-    default_config: dict
-    notes: str | None = None
-
-
-# Common defaults used across most platforms; embedded per-platform
-# below so per-platform overrides remain explicit.
-_DEFAULTS = {
-    "sleep": 3.0,
-    "sleep_request": 1.5,
-    "skip_existing": True,
-    "save_metadata": True,
-    "timeout": 3600,
-}
-
-
-PLATFORMS: dict[str, PlatformInfo] = {
-    "patreon": PlatformInfo(
-        key="patreon",
-        name="Patreon",
-        description="Download posts from Patreon creators",
-        auth_type="cookies",
-        requires_auth=True,
-        url_pattern=r"^https?://(www\.)?patreon\.com/",
-        url_examples=[
-            "https://www.patreon.com/example_artist",
-            "https://www.patreon.com/user?u=12345678",
-        ],
-        default_config={**_DEFAULTS, "content_types": ["images", "attachments"]},
-    ),
-    "subscribestar": PlatformInfo(
-        key="subscribestar",
-        name="SubscribeStar",
-        description="Download posts from SubscribeStar creators",
-        auth_type="cookies",
-        requires_auth=True,
-        url_pattern=r"^https?://(www\.)?subscribestar\.(com|adult)/",
-        url_examples=[
-            "https://subscribestar.adult/example_artist",
-            "https://www.subscribestar.com/example_artist",
-        ],
-        default_config={**_DEFAULTS, "content_types": ["all"]},
-    ),
-    "hentaifoundry": PlatformInfo(
-        key="hentaifoundry",
-        name="Hentai Foundry",
-        description="Download artwork from Hentai Foundry artists",
-        auth_type="cookies",
-        requires_auth=False,
-        url_pattern=r"^https?://(www\.)?hentai-foundry\.com/",
-        url_examples=[
-            "https://www.hentai-foundry.com/user/example_artist",
-            "https://www.hentai-foundry.com/pictures/user/example_artist",
-        ],
-        default_config={**_DEFAULTS, "content_types": ["pictures"]},
-    ),
-    "discord": PlatformInfo(
-        key="discord",
-        name="Discord",
-        description="Download attachments from Discord channels",
-        auth_type="token",
-        requires_auth=True,
-        url_pattern=r"^https?://(www\.)?discord\.com/channels/",
-        url_examples=["https://discord.com/channels/123456789/987654321"],
-        default_config={**_DEFAULTS, "content_types": ["all"]},
-        notes="Requires Discord user token (not bot token).",
-    ),
-    "pixiv": PlatformInfo(
-        key="pixiv",
-        name="Pixiv",
-        description="Download artwork from Pixiv artists",
-        auth_type="token",
-        requires_auth=True,
-        url_pattern=r"^https?://(www\.)?pixiv\.net/",
-        url_examples=[
-            "https://www.pixiv.net/users/12345678",
-            "https://www.pixiv.net/en/users/12345678",
-        ],
-        default_config={**_DEFAULTS, "content_types": ["all"]},
-        notes="Requires OAuth refresh token. Run `gallery-dl oauth:pixiv` to obtain one.",
-    ),
-    "deviantart": PlatformInfo(
-        key="deviantart",
-        name="DeviantArt",
-        description="Download artwork from DeviantArt artists",
-        auth_type="cookies",
-        requires_auth=False,
-        url_pattern=r"^https?://(www\.)?deviantart\.com/",
-        url_examples=[
-            "https://www.deviantart.com/example-artist",
-            "https://www.deviantart.com/example-artist/gallery",
-        ],
-        default_config={**_DEFAULTS, "content_types": ["gallery"]},
-    ),
-}
-
-
-def known_platform_keys() -> frozenset[str]:
-    return frozenset(PLATFORMS.keys())
-
-
-def auth_type_for(platform: str) -> str | None:
-    info = PLATFORMS.get(platform)
-    return info.auth_type if info else None
-
-
-def to_dict(info: PlatformInfo) -> dict:
-    return {
-        "key": info.key,
-        "name": info.name,
-        "description": info.description,
-        "auth_type": info.auth_type,
-        "requires_auth": info.requires_auth,
-        "url_pattern": info.url_pattern,
-        "url_examples": info.url_examples,
-        "default_config": info.default_config,
-        "notes": info.notes,
-    }
@@ -0,0 +1,95 @@
+"""FC-3b platforms registry — single source of truth for what
+FabledCurator supports + where each platform's quirks live.
+
+Adding a new platform: drop a new module `<platform>.py` next to this
+one, declare an `INFO = PlatformInfo(...)`, add the import + entry in
+PLATFORMS below. Sidecar parsing, cookie materialization, and
+`/api/platforms` pick it up automatically.
+
+Lifted from GallerySubscriber's
+~/Nextcloud/Projects/GallerySubscriber/backend/app/api/platforms.py
+and ~/.../extension/lib/platforms.js. Six platforms; auth_type and
+URL patterns match GS exactly so the existing browser extension
+hits FC unmodified.
+"""
+
+from .base import (
+    DEFAULT_DESCRIPTION_KEYS,
+    DEFAULT_EXTERNAL_POST_ID_KEYS,
+    PlatformInfo,
+)
+from .deviantart import INFO as _DEVIANTART
+from .discord import INFO as _DISCORD
+from .hentaifoundry import INFO as _HENTAIFOUNDRY
+from .patreon import INFO as _PATREON
+from .pixiv import INFO as _PIXIV
+from .subscribestar import INFO as _SUBSCRIBESTAR
+
+PLATFORMS: dict[str, PlatformInfo] = {
+    info.key: info
+    for info in (
+        _PATREON,
+        _SUBSCRIBESTAR,
+        _HENTAIFOUNDRY,
+        _DISCORD,
+        _PIXIV,
+        _DEVIANTART,
+    )
+}
+
+
+def known_platform_keys() -> frozenset[str]:
+    return frozenset(PLATFORMS.keys())
+
+
+def auth_type_for(platform: str) -> str | None:
+    info = PLATFORMS.get(platform)
+    return info.auth_type if info else None
+
+
+def to_dict(info: PlatformInfo) -> dict:
+    """Serialize a PlatformInfo to a JSON-safe dict for /api/platforms.
+
+    Behavioral fields (callables, sidecar-chain overrides) are
+    intentionally omitted — they aren't useful to API consumers.
+    """
+    return {
+        "key": info.key,
+        "name": info.name,
+        "description": info.description,
+        "auth_type": info.auth_type,
+        "requires_auth": info.requires_auth,
+        "url_pattern": info.url_pattern,
+        "url_examples": info.url_examples,
+        "default_config": info.default_config,
+        "notes": info.notes,
+    }
+
+
+def external_post_id_keys_for(platform: str | None) -> tuple[str, ...]:
+    """Resolve the external_post_id lookup chain for a given platform,
+    falling back to the module default when the platform isn't
+    registered or hasn't overridden the chain."""
+    info = PLATFORMS.get(platform) if platform else None
+    if info is not None and info.external_post_id_keys is not None:
+        return info.external_post_id_keys
+    return DEFAULT_EXTERNAL_POST_ID_KEYS
+
+
+def description_keys_for(platform: str | None) -> tuple[str, ...]:
+    """Resolve the description body lookup chain for a given platform."""
+    info = PLATFORMS.get(platform) if platform else None
+    if info is not None and info.description_keys is not None:
+        return info.description_keys
+    return DEFAULT_DESCRIPTION_KEYS
+
+
+__all__ = [
+    "PLATFORMS",
+    "PlatformInfo",
+    "auth_type_for",
+    "description_keys_for",
+    "external_post_id_keys_for",
+    "known_platform_keys",
+    "to_dict",
+]
@@ -0,0 +1,107 @@
+"""PlatformInfo dataclass + shared defaults + small helpers.
+
+Per-platform modules import from here, register their PlatformInfo via
+INFO, optionally attaching `derive_post_url` and/or `augment_cookies`
+callables for behavior that diverges from gallery-dl's mainline shape
+(Patreon).
+
+Adding a new platform: drop a new module under `services/platforms/`,
+declare an INFO, and add it to the import list in
+`services/platforms/__init__.py`. Sidecar parsing, cookie
+materialization, and the /api/platforms response pick it up
+automatically.
+"""
+
+from collections.abc import Callable
+from dataclasses import dataclass
+from typing import Literal
+
+# Sidecar parsing defaults. Per-platform PlatformInfo entries can
+# override these by setting `external_post_id_keys=` /
+# `description_keys=`. Most don't need to — the defaults already cover
+# every platform FC supports.
+#
+# external_post_id chain: `post_id` MUST come before `id` because
+# SubscribeStar gallery-dl puts the per-attachment id in `id` and the
+# actual post id in `post_id`; picking `id` first fragments
+# multi-image SubscribeStar posts into N Post rows. Patreon/Pixiv have
+# no `post_id` so `id` still wins for them; HF uses `index`, Discord
+# uses `message_id` — all reached via the remaining chain entries.
+# (Banked 2026-05-27 during the sidecar audit.)
+DEFAULT_EXTERNAL_POST_ID_KEYS: tuple[str, ...] = (
+    "post_id", "id", "index", "message_id",
+)
+
+# Description body chain: Discord's gallery-dl extractor uses `message`
+# (no `content`); appended to the chain so Discord posts surface body
+# text.
+DEFAULT_DESCRIPTION_KEYS: tuple[str, ...] = (
+    "content", "description", "caption", "message",
+)
+
+
+@dataclass(frozen=True)
+class PlatformInfo:
+    # --- Identity / metadata ---
+    key: str
+    name: str
+    description: str
+    auth_type: Literal["cookies", "token"]
+    requires_auth: bool
+    url_pattern: str
+    url_examples: list[str]
+    default_config: dict
+    notes: str | None = None
+
+    # --- Sidecar parsing overrides ---
+    # Each is None to mean "use the module default above"; a platform
+    # only sets one of these when its sidecar shape genuinely differs.
+    external_post_id_keys: tuple[str, ...] | None = None
+    description_keys: tuple[str, ...] | None = None
+
+    # --- Behavioral hooks ---
+    # Synthesize a post permalink from sidecar data. Required when
+    # gallery-dl's `url` field is the file/CDN URL rather than the post
+    # permalink (subscribestar/pixiv/hf/discord). None = trust the bare
+    # `url` field (patreon, deviantart).
+    derive_post_url: Callable[[dict], str | None] | None = None
+
+    # Post-process the materialized cookies.txt for gallery-dl. Used by
+    # platforms whose server gates or extractor quirks need synthetic
+    # cookies the extension can't capture (subscribestar age cookie, HF
+    # host-only PHPSESSID duplicate). None = no-op.
+    augment_cookies: Callable[[str], str] | None = None
+
+
+def str_id_value(v) -> str | None:
+    """Coerce a JSON scalar id into a non-empty string, rejecting bool
+    (Python's bool is an int subclass so `isinstance(True, int)` is
+    True; without this guard a sidecar with `"id": true` would produce
+    external_post_id="True")."""
+    if isinstance(v, bool):
+        return None
+    if isinstance(v, (str, int)) and str(v).strip():
+        return str(v).strip()
+    return None
+
+
+def str_field(v) -> str | None:
+    """Same idea as str_id_value but for plain string fields (no int
+    coercion)."""
+    if isinstance(v, str) and v.strip():
+        return v.strip()
+    return None
+
+
+# Shared gallery-dl invocation defaults. Embedded in each platform's
+# default_config (with platform-specific overrides) so per-platform
+# choices stay explicit.
+# Note: the gallery-dl `skip` value (tick "exit:20" vs backfill True) is
+# NOT here — it's derived from Source.backfill_runs_remaining at download
+# time. See plan #544 / gallery_dl.TICK_SKIP_VALUE,BACKFILL_SKIP_VALUE.
+GD_DEFAULTS = {
+    "sleep": 3.0,
+    "sleep_request": 1.5,
+    "save_metadata": True,
+    "timeout": 3600,
+}
@@ -0,0 +1,23 @@
+"""DeviantArt — no exercised quirks yet.
+
+No operator-owned DeviantArt archive existed at the 2026-05-27 sidecar
+audit, so we don't know yet whether DA's gallery-dl sidecars are
+well-behaved or have their own quirks. When DA gets exercised for the
+first time, add `derive_post_url` / `augment_cookies` here as needed.
+"""
+
+from .base import GD_DEFAULTS, PlatformInfo
+
+INFO = PlatformInfo(
+    key="deviantart",
+    name="DeviantArt",
+    description="Download artwork from DeviantArt artists",
+    auth_type="cookies",
+    requires_auth=False,
+    url_pattern=r"^https?://(www\.)?deviantart\.com/",
+    url_examples=[
+        "https://www.deviantart.com/example-artist",
+        "https://www.deviantart.com/example-artist/gallery",
+    ],
+    default_config={**GD_DEFAULTS, "content_types": ["gallery"]},
+)
@@ -0,0 +1,38 @@
+"""Discord — one quirk + one already-default.
+
+post_url: gallery-dl's `url` is the CDN attachment URL. The "permalink"
+for a Discord message uses the (server, channel, message) triple via
+`discord.com/channels/<server>/<channel>/<message>`. Note that
+permalinks are only resolvable for users in the same server — public
+access doesn't work — but the URL is still useful to the operator
+in-app.
+
+Description body is in `message` not `content`. That's already covered
+by the default description chain in base.py (DEFAULT_DESCRIPTION_KEYS
+ends with `message`). No description_keys override needed.
+"""
+
+from .base import GD_DEFAULTS, PlatformInfo, str_id_value
+
+
+def derive_post_url(data: dict) -> str | None:
+    sid = str_id_value(data.get("server_id"))
+    cid = str_id_value(data.get("channel_id"))
+    mid = str_id_value(data.get("message_id"))
+    if sid and cid and mid:
+        return f"https://discord.com/channels/{sid}/{cid}/{mid}"
+    return None
+
+
+INFO = PlatformInfo(
+    key="discord",
+    name="Discord",
+    description="Download attachments from Discord channels",
+    auth_type="token",
+    requires_auth=True,
+    url_pattern=r"^https?://(www\.)?discord\.com/channels/",
+    url_examples=["https://discord.com/channels/123456789/987654321"],
+    default_config={**GD_DEFAULTS, "content_types": ["all"]},
+    notes="Requires Discord user token (not bot token).",
+    derive_post_url=derive_post_url,
+)
@@ -0,0 +1,83 @@
+"""HentaiFoundry — two quirks colocated.
+
+1. post_url: HF sidecars omit `url` entirely; `src` is the image URL.
+   Synthesize the permalink from `user` + `index`
+   (/pictures/user/<user>/<index>).
+
+2. augment_cookies: gallery-dl's HF extractor checks
+   `self.cookies.get("PHPSESSID", domain="www.hentai-foundry.com")` with
+   `requests`' EXACT domain matching. The extension's pre-v1.0.5
+   `cookies.js` aggressively rewrote every captured cookie to the
+   leading-dot subdomain-wide form (`.hentai-foundry.com`), which fails
+   the exact lookup even though the cookie IS sent on actual HTTP
+   requests (RFC 6265 subdomain matching). The extractor falls into
+   an unauthenticated `?enterAgree=1` HEAD that 401s. Inject host-only
+   duplicates of PHPSESSID + YII_CSRF_TOKEN so the lookup succeeds.
+"""
+
+from .base import GD_DEFAULTS, PlatformInfo, str_field, str_id_value
+
+_HOST_ONLY_NAMES = ("PHPSESSID", "YII_CSRF_TOKEN")
+
+
+def derive_post_url(data: dict) -> str | None:
+    user = str_field(data.get("user")) or str_field(data.get("artist"))
+    idx = str_id_value(data.get("index"))
+    if user and idx:
+        return f"https://www.hentai-foundry.com/pictures/user/{user}/{idx}"
+    return None
+
+
+def augment_cookies(netscape: str) -> str:
+    body = netscape.rstrip("\n")
+    if not body:
+        return netscape
+    lines = body.split("\n")
+    existing_host_only: set[str] = set()
+    by_name: dict[str, list[str]] = {}
+    for raw in lines:
+        if not raw or raw.startswith("#"):
+            continue
+        parts = raw.split("\t")
+        if len(parts) < 7:
+            continue
+        domain, _flag, _path, _secure, _exp, name, _value = parts[:7]
+        if name not in _HOST_ONLY_NAMES:
+            continue
+        if domain == "www.hentai-foundry.com":
+            existing_host_only.add(name)
+        elif domain in (".hentai-foundry.com", "hentai-foundry.com"):
+            by_name.setdefault(name, []).append(raw)
+
+    appended: list[str] = []
+    for name in _HOST_ONLY_NAMES:
+        if name in existing_host_only or name not in by_name:
+            continue
+        # Duplicate the first subdomain-wide line as host-only on
+        # www.hentai-foundry.com. Same value + expiry; flag=FALSE marks
+        # the entry host-only in netscape format.
+        parts = by_name[name][0].split("\t")
+        parts[0] = "www.hentai-foundry.com"
+        parts[1] = "FALSE"
+        appended.append("\t".join(parts[:7]))
+
+    if not appended:
+        return netscape
+    return body + "\n" + "\n".join(appended) + "\n"
+
+
+INFO = PlatformInfo(
+    key="hentaifoundry",
+    name="Hentai Foundry",
+    description="Download artwork from Hentai Foundry artists",
+    auth_type="cookies",
+    requires_auth=False,
+    url_pattern=r"^https?://(www\.)?hentai-foundry\.com/",
+    url_examples=[
+        "https://www.hentai-foundry.com/user/example_artist",
+        "https://www.hentai-foundry.com/pictures/user/example_artist",
+    ],
+    default_config={**GD_DEFAULTS, "content_types": ["pictures"]},
+    derive_post_url=derive_post_url,
+    augment_cookies=augment_cookies,
+)
@@ -0,0 +1,23 @@
+"""Patreon — no quirks. The reference platform.
+
+Patreon's gallery-dl sidecars are the well-behaved baseline: `url` is a
+real permalink, `id` is the post id, `title` and `content` are
+populated. No cookie quirks (session cookies are domain-wide). No
+derivation overrides.
+"""
+
+from .base import GD_DEFAULTS, PlatformInfo
+
+INFO = PlatformInfo(
+    key="patreon",
+    name="Patreon",
+    description="Download posts from Patreon creators",
+    auth_type="cookies",
+    requires_auth=True,
+    url_pattern=r"^https?://(www\.)?patreon\.com/",
+    url_examples=[
+        "https://www.patreon.com/example_artist",
+        "https://www.patreon.com/user?u=12345678",
+    ],
+    default_config={**GD_DEFAULTS, "content_types": ["images", "attachments"]},
+)
@@ -0,0 +1,32 @@
+"""Pixiv — one quirk.
+
+post_url: gallery-dl's `url` is the image URL on `i.pximg.net`. The
+post permalink follows /artworks/<id>. external_post_id (= `id`) was
+already correct, so no override there.
+"""
+
+from .base import GD_DEFAULTS, PlatformInfo, str_id_value
+
+
+def derive_post_url(data: dict) -> str | None:
+    pid = str_id_value(data.get("id"))
+    if pid:
+        return f"https://www.pixiv.net/artworks/{pid}"
+    return None
+
+
+INFO = PlatformInfo(
+    key="pixiv",
+    name="Pixiv",
+    description="Download artwork from Pixiv artists",
+    auth_type="token",
+    requires_auth=True,
+    url_pattern=r"^https?://(www\.)?pixiv\.net/",
+    url_examples=[
+        "https://www.pixiv.net/users/12345678",
+        "https://www.pixiv.net/en/users/12345678",
+    ],
+    default_config={**GD_DEFAULTS, "content_types": ["all"]},
+    notes="Requires OAuth refresh token. Run `gallery-dl oauth:pixiv` to obtain one.",
+    derive_post_url=derive_post_url,
+)
@@ -0,0 +1,62 @@
+"""SubscribeStar — three quirks colocated.
+
+1. external_post_id: gallery-dl puts the per-attachment id in `id`
+   (e.g. 711509) and the actual post id in `post_id` (e.g. 360360).
+   The default chain in base.py already prefers `post_id`; this module
+   doesn't need to override it but the comment lives here too so a
+   future reader knows the chain's order was driven by this platform.
+
+2. post_url: gallery-dl's `url` is the file CDN URL
+   (`/post_uploads?payload=...`). Synthesize the post permalink from
+   `post_id`.
+
+3. augment_cookies: the server gates artist pages behind a
+   `_personalization_id` age-confirmation cookie that the user can't
+   easily refresh — SubscribeStar's frontend JS uses localStorage to
+   suppress the age popup once dismissed. gallery-dl's own login flow
+   sidesteps this by setting `18_plus_agreement_generic=true` on
+   `.subscribestar.adult`; we mirror that for cookies captured via the
+   extension.
+"""
+
+from .base import GD_DEFAULTS, PlatformInfo, str_id_value
+
+
+def derive_post_url(data: dict) -> str | None:
+    pid = str_id_value(data.get("post_id"))
+    if pid:
+        return f"https://www.subscribestar.com/posts/{pid}"
+    return None
+
+
+def augment_cookies(netscape: str) -> str:
+    if "18_plus_agreement_generic" in netscape:
+        return netscape
+    # Far-future expiry — gallery-dl's own login flow sets this with no
+    # explicit expiry; the server only checks presence/value.
+    expiry = 4102444800  # 2100-01-01 UTC
+    line = "\t".join([
+        ".subscribestar.adult", "TRUE", "/", "TRUE",
+        str(expiry), "18_plus_agreement_generic", "true",
+    ])
+    body = netscape.rstrip("\n")
+    if not body:
+        body = "# Netscape HTTP Cookie File"
+    return body + "\n" + line + "\n"
+
+
+INFO = PlatformInfo(
+    key="subscribestar",
+    name="SubscribeStar",
+    description="Download posts from SubscribeStar creators",
+    auth_type="cookies",
+    requires_auth=True,
+    url_pattern=r"^https?://(www\.)?subscribestar\.(com|adult)/",
+    url_examples=[
+        "https://subscribestar.adult/example_artist",
+        "https://www.subscribestar.com/example_artist",
+    ],
+    default_config={**GD_DEFAULTS, "content_types": ["all"]},
+    derive_post_url=derive_post_url,
+    augment_cookies=augment_cookies,
+)
@@ -56,38 +56,67 @@ class PostFeedService:
        artist_id: int | None = None,
        platform: str | None = None,
        limit: int = 24,
+        direction: str = "older",
    ) -> dict:
+        """Paginate the feed from `cursor`. direction='older' walks back in
+        time (default, infinite-scroll down); direction='newer' walks forward
+        (scroll up in an anchored view). Items are always returned in feed
+        (descending) order; `next_cursor` points to the far edge in the
+        requested direction (null when exhausted)."""
        if limit < 1 or limit > 100:
            raise ValueError("limit must be between 1 and 100")
+        if direction not in ("older", "newer"):
+            raise ValueError("direction must be 'older' or 'newer'")

        sort_key = _sort_key()
+        # Artist via the denormalized Post.artist_id (alembic 0030);
+        # Source via LEFT JOIN since post.source_id can now be NULL for
+        # filesystem-imported posts with no live subscription. A
+        # platform= filter implicitly excludes NULL-source posts (they
+        # have no platform); an artist_id= filter still surfaces them
+        # because Post.artist_id is always set.
        stmt = (
            select(Post, Artist, Source)
-            .join(Source, Post.source_id == Source.id)
-            .join(Artist, Source.artist_id == Artist.id)
+            .join(Artist, Post.artist_id == Artist.id)
+            .outerjoin(Source, Post.source_id == Source.id)
        )
        if artist_id is not None:
-            stmt = stmt.where(Source.artist_id == artist_id)
+            stmt = stmt.where(Post.artist_id == artist_id)
        if platform is not None:
            stmt = stmt.where(Source.platform == platform)
        if cursor:
            cur_ts, cur_id = decode_cursor(cursor)
-            stmt = stmt.where(
-                or_(
+            if direction == "older":
+                stmt = stmt.where(or_(
                    sort_key < cur_ts,
                    and_(sort_key == cur_ts, Post.id < cur_id),
-                )
-            )
+                ))
+            else:
+                stmt = stmt.where(or_(
+                    sort_key > cur_ts,
+                    and_(sort_key == cur_ts, Post.id > cur_id),
+                ))

-        stmt = stmt.order_by(sort_key.desc(), Post.id.desc()).limit(limit + 1)
+        if direction == "older":
+            stmt = stmt.order_by(sort_key.desc(), Post.id.desc())
+        else:
+            stmt = stmt.order_by(sort_key.asc(), Post.id.asc())
+        stmt = stmt.limit(limit + 1)
        rows = (await self.session.execute(stmt)).all()

+        has_more = len(rows) > limit
+        rows = rows[:limit]
+        if direction == "newer":
+            # Fetched ascending (closest-newer first); flip to feed order.
+            rows = list(reversed(rows))
+
        next_cursor: str | None = None
-        if len(rows) > limit:
-            last_post, _, _ = rows[limit - 1]
-            last_key = last_post.post_date or last_post.downloaded_at
-            next_cursor = encode_cursor(last_key, last_post.id)
-            rows = rows[:limit]
+        if has_more and rows:
+            # Far edge in the travel direction: oldest row going older,
+            # newest row going newer (rows is descending for display).
+            edge_post = rows[-1][0] if direction == "older" else rows[0][0]
+            edge_key = edge_post.post_date or edge_post.downloaded_at
+            next_cursor = encode_cursor(edge_key, edge_post.id)

        post_ids = [p.id for p, _, _ in rows]
        thumbs_map = await self._thumbnails_for(post_ids)
@@ -99,17 +128,63 @@ class PostFeedService:
        ]
        return {"items": items, "next_cursor": next_cursor}

+    async def around(
+        self,
+        *,
+        post_id: int,
+        artist_id: int | None = None,
+        platform: str | None = None,
+        limit: int = 12,
+    ) -> dict | None:
+        """A window centered on `post_id`: up to `limit` newer posts + the
+        post + up to `limit` older posts, in feed (descending) order, with a
+        cursor for each end. Returns None if the post doesn't exist."""
+        anchor = (await self.session.execute(
+            select(Post, Artist, Source)
+            .join(Artist, Post.artist_id == Artist.id)
+            .outerjoin(Source, Post.source_id == Source.id)
+            .where(Post.id == post_id)
+        )).one_or_none()
+        if anchor is None:
+            return None
+        anchor_post, anchor_artist, anchor_source = anchor
+        anchor_key = anchor_post.post_date or anchor_post.downloaded_at
+        anchor_cursor = encode_cursor(anchor_key, anchor_post.id)
+
+        older = await self.scroll(
+            cursor=anchor_cursor, artist_id=artist_id, platform=platform,
+            limit=limit, direction="older",
+        )
+        newer = await self.scroll(
+            cursor=anchor_cursor, artist_id=artist_id, platform=platform,
+            limit=limit, direction="newer",
+        )
+        thumbs_map = await self._thumbnails_for([anchor_post.id])
+        atts_map = await self._attachments_for([anchor_post.id])
+        anchor_item = self._to_dict(
+            anchor_post, anchor_artist, anchor_source, thumbs_map, atts_map,
+        )
+        return {
+            "items": newer["items"] + [anchor_item] + older["items"],
+            "cursor_older": older["next_cursor"],
+            "cursor_newer": newer["next_cursor"],
+            "anchor_id": anchor_post.id,
+        }
+
    async def get_post(self, post_id: int) -> dict | None:
        row = (await self.session.execute(
            select(Post, Artist, Source)
-            .join(Source, Post.source_id == Source.id)
-            .join(Artist, Source.artist_id == Artist.id)
+            .join(Artist, Post.artist_id == Artist.id)
+            .outerjoin(Source, Post.source_id == Source.id)
            .where(Post.id == post_id)
        )).one_or_none()
        if row is None:
            return None
        post, artist, source = row
-        thumbs_map = await self._thumbnails_for([post.id])
+        # Detail endpoint returns the FULL image list for PostModal's
+        # masonry grid — feed query still caps at THUMBNAIL_LIMIT via
+        # the default arg.
+        thumbs_map = await self._thumbnails_for([post.id], limit=None)
        atts_map = await self._attachments_for([post.id])
        item = self._to_dict(post, artist, source, thumbs_map, atts_map)
        item["description_full"] = html_to_plain(post.description)
@@ -117,21 +192,28 @@ class PostFeedService:

    # --- composition helpers ---------------------------------------------

-    async def _thumbnails_for(self, post_ids: list[int]) -> dict[int, dict]:
-        """post_id -> {"thumbs": [...up to 6], "more": int}.
+    async def _thumbnails_for(
+        self, post_ids: list[int], *, limit: int | None = THUMBNAIL_LIMIT,
+    ) -> dict[int, dict]:
+        """post_id -> {"thumbs": [...up to limit], "more": int}.

-        Selects THUMBNAIL_LIMIT+1 images per post via window function so we
-        can detect overflow in a single query.
+        Selects up to `limit` images per post via window function so we
+        can detect overflow in a single query. Pass `limit=None` to
+        return ALL thumbnails per post (used by `get_post` for PostModal's
+        masonry grid; the feed pass keeps the default cap so payloads
+        stay small).
        """
        if not post_ids:
            return {}
-        # Rank images within each post and fetch only the top THUMBNAIL_LIMIT+1.
+        # Rank images within each post; cap at `limit` rows per post when
+        # limit is set, return all when limit is None.
        ranked = (
            select(
                ImageRecord.id,
                ImageRecord.primary_post_id,
                ImageRecord.sha256,
                ImageRecord.mime,
+                ImageRecord.thumbnail_path,
                func.row_number().over(
                    partition_by=ImageRecord.primary_post_id,
                    order_by=ImageRecord.id.asc(),
@@ -143,19 +225,20 @@ class PostFeedService:
            .where(ImageRecord.primary_post_id.in_(post_ids))
            .subquery()
        )
-        rows = (await self.session.execute(
-            select(
-                ranked.c.id, ranked.c.primary_post_id,
-                ranked.c.sha256, ranked.c.mime, ranked.c.total,
-            ).where(ranked.c.rn <= THUMBNAIL_LIMIT)
-        )).all()
+        stmt = select(
+            ranked.c.id, ranked.c.primary_post_id,
+            ranked.c.sha256, ranked.c.mime, ranked.c.thumbnail_path, ranked.c.total,
+        )
+        if limit is not None:
+            stmt = stmt.where(ranked.c.rn <= limit)
+        rows = (await self.session.execute(stmt)).all()

        out: dict[int, dict] = {pid: {"thumbs": [], "more": 0} for pid in post_ids}
-        for img_id, pid, sha, mime, total in rows:
+        for img_id, pid, sha, mime, tp, total in rows:
            entry = out.setdefault(pid, {"thumbs": [], "more": 0})
            entry["thumbs"].append({
                "image_id": img_id,
-                "thumbnail_url": thumbnail_url(sha, mime),
+                "thumbnail_url": thumbnail_url(tp, sha, mime),
                "mime": mime,
            })
            # `total` is constant per partition; overflow = total - THUMBNAIL_LIMIT.
@@ -183,7 +266,7 @@ class PostFeedService:
        return out

    def _to_dict(
-        self, post: Post, artist: Artist, source: Source,
+        self, post: Post, artist: Artist, source: Source | None,
        thumbs_map: dict, atts_map: dict,
    ) -> dict:
        plain_full = html_to_plain(post.description) if post.description else None
@@ -192,6 +275,9 @@ class PostFeedService:
        else:
            description_plain, truncated = truncate_at_word(plain_full, DESCRIPTION_LIMIT)
        thumbs_entry = thumbs_map.get(post.id, {"thumbs": [], "more": 0})
+        # `source` is null for filesystem-imported posts with no live
+        # subscription (alembic 0030). Frontend renders that as a
+        # "filesystem import" affordance instead of a platform chip.
        return {
            "id": post.id,
            "external_post_id": post.external_post_id,
@@ -202,7 +288,10 @@ class PostFeedService:
            "description_plain": description_plain,
            "description_truncated": truncated,
            "artist": {"id": artist.id, "name": artist.name, "slug": artist.slug},
-            "source": {"id": source.id, "platform": source.platform},
+            "source": (
+                {"id": source.id, "platform": source.platform}
+                if source is not None else None
+            ),
            "thumbnails": thumbs_entry["thumbs"],
            "thumbnails_more": thumbs_entry["more"],
            "attachments": atts_map.get(post.id, []),
@@ -70,11 +70,15 @@ class ProvenanceService:
        rec = await self.session.get(ImageRecord, image_id)
        if rec is None:
            return None
+        # Artist via Post.artist_id (alembic 0030); Source via LEFT JOIN
+        # since both Post.source_id and ImageProvenance.source_id can be
+        # NULL for filesystem-imported content. Frontend renders source=
+        # null as "filesystem import."
        stmt = (
            select(ImageProvenance, Post, Source, Artist)
            .join(Post, Post.id == ImageProvenance.post_id)
-            .join(Source, Source.id == ImageProvenance.source_id)
-            .join(Artist, Artist.id == Source.artist_id)
+            .join(Artist, Artist.id == Post.artist_id)
+            .outerjoin(Source, Source.id == ImageProvenance.source_id)
            .where(ImageProvenance.image_record_id == image_id)
            .order_by(ImageProvenance.captured_at.asc(),
                      ImageProvenance.id.asc())
@@ -90,7 +94,7 @@ class ProvenanceService:
                    "captured_at": ip.captured_at.isoformat()
                    if ip.captured_at else None,
                    "post": _post_dict(post),
-                    "source": _source_dict(src),
+                    "source": _source_dict(src) if src is not None else None,
                    "artist": _artist_dict(art),
                }
                for ip, post, src, art in rows
@@ -99,10 +103,12 @@ class ProvenanceService:
        }

    async def for_post(self, post_id: int) -> dict | None:
+        # Same LEFT JOIN to Source — get_post must succeed for a
+        # NULL-source post.
        stmt = (
            select(Post, Source, Artist)
-            .join(Source, Source.id == Post.source_id)
-            .join(Artist, Artist.id == Source.artist_id)
+            .join(Artist, Artist.id == Post.artist_id)
+            .outerjoin(Source, Source.id == Post.source_id)
            .where(Post.id == post_id)
        )
        row = (await self.session.execute(stmt)).first()
@@ -111,7 +117,7 @@ class ProvenanceService:
        post, src, art = row
        return {
            "post": _post_dict(post),
-            "source": _source_dict(src),
+            "source": _source_dict(src) if src is not None else None,
            "artist": _artist_dict(art),
            "attachments": await self._attachments_for_posts([post.id]),
        }
@@ -0,0 +1,106 @@
+"""Layer-2 one-shot re-download remediation for corrupt imported files.
+
+When an import fails on a file that came from a known, pollable
+subscription Source, deleting the bad copy and re-running the source's
+downloader can fetch a fresh, unblemished copy. This only helps when:
+
+  - the corruption is in transit / on disk (not at the source), AND
+  - the file resolves to an ENABLED Source with a real feed URL
+    (a `sidecar:<platform>:<slug>` synthetic anchor is not pollable),
+    AND
+  - we haven't already re-fetched this task once (bounded by
+    ImportTask.refetched so source-side corruption can't loop).
+
+Filesystem-only imports with no resolvable Source return 'no_source' —
+the operator's only remediation there is to replace the file on disk.
+
+Operator-requested 2026-05-28 (Layer 2).
+"""
+
+import json
+import logging
+from pathlib import Path
+
+from sqlalchemy import select
+from sqlalchemy.orm import Session
+
+from ..models import Artist, ImportTask, Source
+from ..utils.paths import derive_top_level_artist
+from ..utils.sidecar import find_sidecar, parse_sidecar
+from ..utils.slug import slugify
+
+log = logging.getLogger(__name__)
+
+
+def resolve_refetch_source(
+    session: Session, source_path: str, import_root: Path,
+) -> Source | None:
+    """Find an enabled, real-URL Source for the file's (artist, platform),
+    or None when nothing re-pollable resolves."""
+    path = Path(source_path)
+    sc = find_sidecar(path)
+    if sc is None:
+        return None
+    try:
+        data = json.loads(sc.read_text("utf-8"))
+    except (OSError, json.JSONDecodeError):
+        return None
+    if not isinstance(data, dict):
+        return None
+    sd = parse_sidecar(data)
+    if not sd.platform:
+        return None
+    artist_name = derive_top_level_artist(path, import_root)
+    if not artist_name:
+        return None
+    artist = session.execute(
+        select(Artist).where(Artist.slug == slugify(artist_name))
+    ).scalar_one_or_none()
+    if artist is None:
+        return None
+    src = session.execute(
+        select(Source)
+        .where(
+            Source.artist_id == artist.id,
+            Source.platform == sd.platform,
+            Source.enabled.is_(True),
+        )
+        .order_by(Source.id.asc())
+    ).scalars().first()
+    if src is None:
+        return None
+    if (src.url or "").startswith("sidecar:"):
+        return None  # synthetic anchor — not a pollable feed
+    return src
+
+
+def attempt_refetch(
+    session: Session, task: ImportTask, import_root: Path,
+) -> dict:
+    """Delete the corrupt file, mark the task refetched, and trigger ONE
+    source re-check. Idempotent/bounded: a task already refetched (or
+    with no resolvable Source) is a no-op. Commits."""
+    if task.refetched:
+        return {"status": "already_refetched"}
+    src = resolve_refetch_source(session, task.source_path, import_root)
+    if src is None:
+        return {"status": "no_source"}
+
+    # Remove the bad copy so gallery-dl's archive-skip re-fetches it on
+    # the source re-check instead of skipping the still-present corrupt
+    # file.
+    try:
+        Path(task.source_path).unlink(missing_ok=True)
+    except OSError as exc:
+        log.warning("refetch unlink failed for %s: %s", task.source_path, exc)
+
+    task.refetched = True
+    session.add(task)
+    session.commit()
+
+    # Lazy import to avoid a tasks→services→tasks import cycle at module
+    # load. download_source.delay() is sync-safe in any context.
+    from ..tasks.download import download_source
+
+    download_source.delay(src.id)
+    return {"status": "refetch_queued", "source_id": src.id}
@@ -9,15 +9,33 @@ from __future__ import annotations
 from datetime import UTC, datetime, timedelta

 from sqlalchemy import select
+from sqlalchemy.dialects.postgresql import insert as pg_insert
 from sqlalchemy.ext.asyncio import AsyncSession
 from sqlalchemy.orm import selectinload

-from ..models import Artist, ImportSettings, Source
+from ..models import AppSetting, Artist, ImportSettings, Source

 MIN_INTERVAL_SECONDS = 60
 MAX_INTERVAL_SECONDS = 86400
 MAX_BACKOFF_EXPONENT = 6

+# AppSetting key stamped every time the Beat tick fires (see scan.py). The
+# tick runs every 60s; the UI flags the scheduler as stalled if the last
+# stamp is older than a few minutes.
+SCHEDULER_LAST_TICK_KEY = "scheduler_last_tick_at"
+
+# AppSetting key prefix for per-platform rate-limit cooldowns. When a
+# download surfaces ErrorType.RATE_LIMITED, every other source on the same
+# platform is deferred for PLATFORM_RATE_LIMIT_COOLDOWN_SECONDS so the next
+# scan tick doesn't fire a burst of due same-platform sources back into the
+# same limit. Per-source consecutive_failures backoff still applies on top
+# of this — but this is PREVENTIVE (kills the same-tick burst from N due
+# sources hammering the platform at once), while consecutive_failures is
+# REACTIVE (slows the offender down over many cycles). Operator-confirmed
+# 2026-05-30.
+PLATFORM_COOLDOWN_KEY_PREFIX = "platform_cooldown:"
+PLATFORM_RATE_LIMIT_COOLDOWN_SECONDS = 900  # 15 min
+

 def compute_effective_interval(
    source: Source, artist: Artist, settings: ImportSettings,
@@ -40,10 +58,76 @@ def compute_effective_interval(
    return max(MIN_INTERVAL_SECONDS, min(MAX_INTERVAL_SECONDS, raw))


+async def set_platform_cooldown(
+    session: AsyncSession, platform: str,
+    seconds: int = PLATFORM_RATE_LIMIT_COOLDOWN_SECONDS,
+) -> None:
+    """Stamp a cooldown expiry on the given platform so select_due_sources
+    skips every source on that platform until it expires.
+
+    Called when a download surfaces ErrorType.RATE_LIMITED so the other
+    sources on the same platform don't all retry into the same rate limit.
+    Caller is responsible for committing the session.
+
+    Uses INSERT...ON CONFLICT DO UPDATE so two concurrent workers hitting
+    the same platform's rate limit don't race: a SELECT-then-INSERT pattern
+    would let the loser's whole transaction (including the source-health
+    update + event finalize) roll back on a unique-violation, stranding
+    that event. Atomic upsert avoids that.
+    """
+    now = datetime.now(UTC)
+    expires_at = (now + timedelta(seconds=seconds)).isoformat()
+    key = f"{PLATFORM_COOLDOWN_KEY_PREFIX}{platform}"
+    stmt = pg_insert(AppSetting.__table__).values(
+        key=key, value=expires_at, updated_at=now,
+    ).on_conflict_do_update(
+        index_elements=["key"],
+        set_={"value": expires_at, "updated_at": now},
+    )
+    await session.execute(stmt)
+
+
+async def active_platform_cooldowns(session: AsyncSession) -> dict[str, datetime]:
+    """Return {platform: expires_at} for platforms whose cooldown is still
+    in the future. Expired rows are ignored (a future maintenance sweep can
+    delete them; they don't affect routing decisions on their own).
+
+    Exposed beyond scheduler_service so the manual check endpoint
+    (`/api/sources/<id>/check`) can defer bulk retries that would bowl
+    into the same rate limit the cooldown is preventing.
+    """
+    rows = (await session.execute(
+        select(AppSetting.key, AppSetting.value)
+        .where(AppSetting.key.startswith(PLATFORM_COOLDOWN_KEY_PREFIX))
+    )).all()
+    if not rows:
+        return {}
+    now = datetime.now(UTC)
+    active: dict[str, datetime] = {}
+    for key, value in rows:
+        try:
+            expires_at = datetime.fromisoformat(value)
+        except (ValueError, TypeError):
+            continue
+        if expires_at > now:
+            active[key[len(PLATFORM_COOLDOWN_KEY_PREFIX):]] = expires_at
+    return active
+
+
 async def select_due_sources(session: AsyncSession) -> list[Source]:
    """Sources where (enabled, artist.auto_check) and now >= last_checked_at + effective_interval.

-    Never-checked sources (last_checked_at IS NULL) are always due.
+    Never-checked sources (last_checked_at IS NULL) are always due. Sources
+    whose platform is currently in a rate-limit cooldown are excluded — the
+    cooldown is the preventive half of the burst-prevention pair (per-source
+    consecutive_failures backoff handles the offending source itself).
+
+    Ordering: last_checked_at ASC NULLS FIRST, then id. Never-checked
+    sources go first, then the longest-since-checked, so the most overdue
+    sources hit Celery's FIFO download queue first. Anti-starvation: if
+    queue throughput ever falls below the tick rate, a freshly-rerun source
+    can't keep cutting in line ahead of one that hasn't been checked at all.
+    Operator-confirmed 2026-05-30.
    """
    rows = (await session.execute(
        select(Source)
@@ -51,15 +135,17 @@ async def select_due_sources(session: AsyncSession) -> list[Source]:
        .join(Artist, Source.artist_id == Artist.id)
        .where(Source.enabled.is_(True))
        .where(Artist.auto_check.is_(True))
+        .order_by(Source.last_checked_at.asc().nulls_first(), Source.id)
    )).scalars().all()

-    settings = (await session.execute(
-        select(ImportSettings).where(ImportSettings.id == 1)
-    )).scalar_one()
+    cooldowns = await active_platform_cooldowns(session)
+    settings = await ImportSettings.load(session)

    now = datetime.now(UTC)
    due: list[Source] = []
    for s in rows:
+        if s.platform in cooldowns:
+            continue
        interval = compute_effective_interval(s, s.artist, settings)
        if s.last_checked_at is None:
            due.append(s)
@@ -78,3 +164,65 @@ def compute_next_check_at(
        return None
    interval = compute_effective_interval(source, artist, settings)
    return source.last_checked_at + timedelta(seconds=interval)
+
+
+async def record_tick(session: AsyncSession) -> None:
+    """Stamp the current time on the SCHEDULER_LAST_TICK_KEY AppSetting.
+
+    Called once per Beat tick so the UI can prove the scheduler is alive.
+    Commits its own write so the stamp survives even if the rest of the
+    tick errors out.
+    """
+    now_iso = datetime.now(UTC).isoformat()
+    row = (await session.execute(
+        select(AppSetting).where(AppSetting.key == SCHEDULER_LAST_TICK_KEY)
+    )).scalar_one_or_none()
+    if row is None:
+        session.add(AppSetting(key=SCHEDULER_LAST_TICK_KEY, value=now_iso))
+    else:
+        row.value = now_iso
+    await session.commit()
+
+
+async def scheduler_status(session: AsyncSession) -> dict:
+    """Summarise scheduler health for the dashboard.
+
+    Returns last_tick_at (when Beat last fired), next_due_at (earliest
+    upcoming scheduled check across enabled auto-check sources), due_now
+    (how many are due right now), and auto_sources (total under schedule).
+    """
+    last_tick_at = (await session.execute(
+        select(AppSetting.value).where(AppSetting.key == SCHEDULER_LAST_TICK_KEY)
+    )).scalar_one_or_none()
+
+    rows = (await session.execute(
+        select(Source)
+        .options(selectinload(Source.artist))
+        .join(Artist, Source.artist_id == Artist.id)
+        .where(Source.enabled.is_(True))
+        .where(Artist.auto_check.is_(True))
+    )).scalars().all()
+    settings = await ImportSettings.load(session)
+
+    now = datetime.now(UTC)
+    due_now = 0
+    next_due_at: datetime | None = None
+    for s in rows:
+        if s.last_checked_at is None:
+            due_now += 1
+            continue
+        nca = compute_next_check_at(s, s.artist, settings)
+        if nca is None or nca <= now:
+            due_now += 1
+        elif next_due_at is None or nca < next_due_at:
+            next_due_at = nca
+
+    cooldowns = await active_platform_cooldowns(session)
+
+    return {
+        "last_tick_at": last_tick_at,
+        "next_due_at": next_due_at.isoformat() if next_due_at else None,
+        "due_now": due_now,
+        "auto_sources": len(rows),
+        "platform_cooldowns": {p: dt.isoformat() for p, dt in cooldowns.items()},
+    }
@@ -63,6 +63,7 @@ class SeriesService:
                    ImageRecord.sha256,
                    ImageRecord.mime,
                    ImageRecord.path,
+                    ImageRecord.thumbnail_path,
                )
                .join(ImageRecord, ImageRecord.id == SeriesPage.image_id)
                .where(SeriesPage.series_tag_id == series_tag_id)
@@ -75,7 +76,7 @@ class SeriesService:
                {
                    "image_id": r.image_id,
                    "page_number": r.page_number,
-                    "thumbnail_url": thumbnail_url(r.sha256, r.mime),
+                    "thumbnail_url": thumbnail_url(r.thumbnail_path, r.sha256, r.mime),
                    "image_url": f"/images/{r.path.split('/images/', 1)[-1]}",
                }
                for r in rows
@@ -34,7 +34,7 @@ class ShowcaseService:
                "mime": r.mime,
                "width": r.width,
                "height": r.height,
-                "thumbnail_url": thumbnail_url(r.sha256, r.mime),
+                "thumbnail_url": thumbnail_url(r.thumbnail_path, r.sha256, r.mime),
            }
            for r in rows
        ]
@@ -59,9 +59,11 @@ class SourceRecord:
    config_overrides: dict | None
    last_checked_at: str | None
    last_error: str | None
+    error_type: str | None
    check_interval_override: int | None
    consecutive_failures: int
    next_check_at: str | None
+    backfill_runs_remaining: int

    def to_dict(self) -> dict:
        return {
@@ -75,9 +77,11 @@ class SourceRecord:
            "config_overrides": self.config_overrides,
            "last_checked_at": self.last_checked_at,
            "last_error": self.last_error,
+            "error_type": self.error_type,
            "check_interval_override": self.check_interval_override,
            "consecutive_failures": self.consecutive_failures,
            "next_check_at": self.next_check_at,
+            "backfill_runs_remaining": self.backfill_runs_remaining,
        }


@@ -85,6 +89,11 @@ class SourceRecord:

 _EDITABLE = {"enabled", "url", "config_overrides", "check_interval_override", "platform"}

+# Plan #544 follow-up: newly created enabled sources pre-arm backfill so
+# their first N polls walk gallery-dl's full post history with the longer
+# timeout (matches the manual "Deep scan" button's default).
+NEW_SOURCE_BACKFILL_RUNS = 3
+

 class SourceService:
    def __init__(self, session: AsyncSession):
@@ -120,9 +129,7 @@ class SourceService:
        return config

    async def _load_settings(self) -> ImportSettings:
-        return (await self.session.execute(
-            select(ImportSettings).where(ImportSettings.id == 1)
-        )).scalar_one()
+        return await ImportSettings.load(self.session)

    def _build_record(
        self, source: Source, artist: Artist, settings: ImportSettings,
@@ -139,9 +146,11 @@ class SourceService:
            config_overrides=source.config_overrides,
            last_checked_at=source.last_checked_at.isoformat() if source.last_checked_at else None,
            last_error=source.last_error,
+            error_type=source.error_type,
            check_interval_override=source.check_interval_override,
            consecutive_failures=source.consecutive_failures or 0,
            next_check_at=nxt.isoformat() if nxt else None,
+            backfill_runs_remaining=source.backfill_runs_remaining or 0,
        )

    async def _row_to_record(self, source: Source) -> SourceRecord:
@@ -151,14 +160,27 @@ class SourceService:
        settings = await self._load_settings()
        return self._build_record(source, artist, settings)

-    async def list(self, artist_id: int | None = None) -> list[SourceRecord]:
-        stmt = (
-            select(Source, Artist)
-            .join(Artist, Artist.id == Source.artist_id)
-            .order_by(Artist.name.asc(), Source.id.asc())
-        )
+    async def list(
+        self, artist_id: int | None = None, failing: bool = False,
+        include_synthetic: bool = False,
+    ) -> list[SourceRecord]:
+        stmt = select(Source, Artist).join(Artist, Artist.id == Source.artist_id)
        if artist_id is not None:
            stmt = stmt.where(Source.artist_id == artist_id)
+        if not include_synthetic:
+            # Pre-alembic-0030 sidecar synthetic anchors
+            # have url='sidecar:<platform>:<slug>' and exist only to give
+            # imported Posts a NOT-NULL Source FK. They aren't pollable
+            # feeds; the Subscriptions UI used to render them as phantom
+            # subscriptions. Hide by default.
+            stmt = stmt.where(~Source.url.like("sidecar:%"))
+        if failing:
+            # Worst-first so the rollup card surfaces the loudest failures.
+            stmt = stmt.where(Source.consecutive_failures > 0).order_by(
+                Source.consecutive_failures.desc(), Artist.name.asc(),
+            )
+        else:
+            stmt = stmt.order_by(Artist.name.asc(), Source.id.asc())
        rows = (await self.session.execute(stmt)).all()
        settings = await self._load_settings()
        return [self._build_record(s, a, settings) for s, a in rows]
@@ -190,10 +212,21 @@ class SourceService:
            select(func.count(Source.id)).where(Source.artist_id == artist_id)
        )).scalar_one()

+        # Plan #544 follow-up: a freshly added subscription has no archive
+        # yet, so the first few polls would walk the full post history in
+        # tick mode and trip exit:20 after ~20 contiguous archive hits —
+        # except there are none yet, so tick mode would walk forever and
+        # blow the wall-clock cap. Pre-arm backfill so the initial syncs
+        # use the longer timeout + skip:True walk. Tick mode resumes once
+        # the budget is spent or the queue drains.
+        # Disabled sources (incl. sidecar synthetics, url='sidecar:...')
+        # are never polled, so leave their counter at 0.
+        backfill_runs = NEW_SOURCE_BACKFILL_RUNS if enabled else 0
        source = Source(
            artist_id=artist_id, platform=platform, url=url,
            enabled=enabled, config_overrides=config_overrides,
            check_interval_override=check_interval_override,
+            backfill_runs_remaining=backfill_runs,
        )
        self.session.add(source)
        try:
@@ -253,6 +286,25 @@ class SourceService:
        await self.session.commit()
        return await self._row_to_record(source)

+    async def set_backfill_runs(
+        self, source_id: int, runs: int,
+    ) -> SourceRecord:
+        """Plan #544: arm a source for backfill mode. The next `runs`
+        download runs will use gallery-dl's full-walk config (skip: True
+        + 30-min timeout) instead of the catch-up default. Runs must be
+        1..10 — bigger is rejected to keep the operator from accidentally
+        setting a runaway budget."""
+        if not isinstance(runs, int) or runs < 1 or runs > 10:
+            raise ValueError("runs must be an integer in [1, 10]")
+        source = (await self.session.execute(
+            select(Source).where(Source.id == source_id)
+        )).scalar_one_or_none()
+        if source is None:
+            raise LookupError(f"source id={source_id} not found")
+        source.backfill_runs_remaining = runs
+        await self.session.commit()
+        return await self._row_to_record(source)
+
    async def delete(self, source_id: int) -> None:
        source = (await self.session.execute(
            select(Source).where(Source.id == source_id)
@@ -115,12 +115,17 @@ class TagDirectoryService:
            .subquery()
        )
        stmt = (
-            select(sub.c.tag_id, ImageRecord.sha256, ImageRecord.mime)
+            select(
+                sub.c.tag_id,
+                ImageRecord.sha256,
+                ImageRecord.mime,
+                ImageRecord.thumbnail_path,
+            )
            .join(ImageRecord, ImageRecord.id == sub.c.image_record_id)
            .where(sub.c.rn <= 3)
            .order_by(sub.c.tag_id, sub.c.rn)
        )
        out: dict[int, list[str]] = {}
-        for tag_id, sha, mime in (await self.session.execute(stmt)).all():
-            out.setdefault(tag_id, []).append(thumbnail_url(sha, mime))
+        for tag_id, sha, mime, tp in (await self.session.execute(stmt)).all():
+            out.setdefault(tag_id, []).append(thumbnail_url(tp, sha, mime))
        return out
@@ -5,6 +5,7 @@ from dataclasses import dataclass

 from sqlalchemy import and_, case, exists, func, select, text, update
 from sqlalchemy.dialects.postgresql import insert as pg_insert
+from sqlalchemy.exc import IntegrityError
 from sqlalchemy.ext.asyncio import AsyncSession

 from ..models import Tag, TagKind, image_tag
@@ -86,9 +87,12 @@ class TagService:
                    f"fandom_id {fandom_id} does not reference a fandom tag"
                )

-        # Upsert via INSERT ... ON CONFLICT DO NOTHING. We can't use the
-        # uniqueness index name directly (it's a partial coalesce-based
-        # expression), so we re-select after insert.
+        # Audit 2026-06-02: race-safe upsert via savepoint +
+        # IntegrityError recovery. The partial uniqueness index on
+        # (name, kind, COALESCE(fandom_id, -1)) catches concurrent
+        # inserts; without the savepoint the outer transaction would
+        # poison and the calling request crashes. Mirrors
+        # importer._get_or_create.
        stmt = (
            select(Tag)
            .where(Tag.name == name)
@@ -101,10 +105,16 @@ class TagService:
        if existing:
            return existing

-        new_tag = Tag(name=name, kind=kind, fandom_id=fandom_id)
-        self.session.add(new_tag)
-        await self.session.flush()
-        return new_tag
+        sp = await self.session.begin_nested()
+        try:
+            new_tag = Tag(name=name, kind=kind, fandom_id=fandom_id)
+            self.session.add(new_tag)
+            await self.session.flush()
+            await sp.commit()
+            return new_tag
+        except IntegrityError:
+            await sp.rollback()
+            return (await self.session.execute(stmt)).scalar_one()

    async def autocomplete(
        self,
@@ -0,0 +1,21 @@
+"""Per-invocation async session factory for Celery task modules.
+
+Async engine connections are bound to the event loop. Each Celery task
+runs its async body under a fresh ``asyncio.run()`` loop, so it needs its
+own engine created (and disposed) within that loop — a process-wide async
+engine would reuse loop-bound connections across tasks and raise "attached
+to a different loop". So unlike the process-wide sync engine in
+``_sync_engine.py``, this returns a fresh engine per call; the caller
+disposes it (``await engine.dispose()``) when its loop ends.
+"""
+
+from sqlalchemy.ext.asyncio import AsyncSession, async_sessionmaker, create_async_engine
+
+from ..config import get_config
+
+
+def async_session_factory():
+    """Return ``(sessionmaker, engine)`` bound to a fresh async engine."""
+    cfg = get_config()
+    engine = create_async_engine(cfg.database_url, future=True, pool_pre_ping=True)
+    return async_sessionmaker(engine, class_=AsyncSession, expire_on_commit=False), engine
@@ -240,15 +240,16 @@ def prune_backups() -> dict:

    Returns {"db_deleted": N, "images_deleted": M, "files_unlinked": K}.
    Tagged rows (tag IS NOT NULL) are never pruned.
-    Status='running' / 'restoring' rows are never pruned (recovery
-    sweep from FC-3i handles those via task_run).
+    Status='running' / 'restoring' rows are never pruned — the
+    recover_stalled_backup_runs sweep flips truly-stuck ones to
+    'error' first. (Earlier docstring claimed the FC-3i TaskRun sweep
+    handled those, but TaskRun cleanup never touched BackupRun rows.
+    Audit 2026-06-02 added the dedicated sweep.)
    """
    SessionLocal = _sync_session_factory()
    counts = {"db_deleted": 0, "images_deleted": 0, "files_unlinked": 0}
    with SessionLocal() as session:
-        s = session.execute(
-            select(ImportSettings).where(ImportSettings.id == 1)
-        ).scalar_one()
+        s = ImportSettings.load_sync(session)
        for kind, keep in (
            ("db", s.backup_db_keep_last_n),
            ("images", s.backup_images_keep_last_n),
@@ -286,9 +287,7 @@ def backup_db_nightly() -> dict:
    either {'skipped': '<reason>'} or {'dispatched': '<task_id>'}."""
    SessionLocal = _sync_session_factory()
    with SessionLocal() as session:
-        s = session.execute(
-            select(ImportSettings).where(ImportSettings.id == 1)
-        ).scalar_one()
+        s = ImportSettings.load_sync(session)
        nightly_enabled = s.backup_db_nightly_enabled
        configured_hour = s.backup_db_nightly_hour_utc
    if not nightly_enabled:
@@ -3,12 +3,9 @@
 import asyncio
 from pathlib import Path

-from sqlalchemy import select
 from sqlalchemy.exc import DBAPIError, OperationalError
-from sqlalchemy.ext.asyncio import AsyncSession, async_sessionmaker, create_async_engine

 from ..celery_app import celery
-from ..config import get_config
 from ..models import ImportSettings
 from ..services.credential_crypto import CredentialCrypto
 from ..services.credential_service import CredentialService
@@ -16,18 +13,13 @@ from ..services.download_service import DownloadService
 from ..services.gallery_dl import GalleryDLService
 from ..services.importer import Importer
 from ..services.thumbnailer import Thumbnailer
+from ._async_session import async_session_factory
 from .import_file import _sync_session_factory

 IMAGES_ROOT = Path("/images")
 _KEY_PATH = IMAGES_ROOT / "secrets" / "credential_key.b64"


-def _async_session_factory():
-    cfg = get_config()
-    engine = create_async_engine(cfg.database_url, future=True, pool_pre_ping=True)
-    return async_sessionmaker(engine, class_=AsyncSession, expire_on_commit=False), engine
-
-
@celery.task(
    name="backend.app.tasks.download.download_source",
    bind=True,
@@ -44,13 +36,11 @@ def download_source(self, source_id: int) -> int:
    """Returns the DownloadEvent.id."""

    async def _run():
-        async_factory, async_engine = _async_session_factory()
+        async_factory, async_engine = async_session_factory()
        SyncFactory = _sync_session_factory()
        try:
            with SyncFactory() as sync_session:
-                settings = sync_session.execute(
-                    select(ImportSettings).where(ImportSettings.id == 1)
-                ).scalar_one()
+                settings = ImportSettings.load_sync(sync_session)
                rate_limit = settings.download_rate_limit_seconds
                validate_files = settings.download_validate_files

@@ -64,9 +54,7 @@ def download_source(self, source_id: int) -> int:
            async with async_factory() as async_session:
                cred_service = CredentialService(async_session, crypto)
                with SyncFactory() as sync_session:
-                    sync_settings = sync_session.execute(
-                        select(ImportSettings).where(ImportSettings.id == 1)
-                    ).scalar_one()
+                    sync_settings = ImportSettings.load_sync(sync_session)
                    importer = Importer(
                        session=sync_session,
                        images_root=IMAGES_ROOT,
@@ -64,30 +64,13 @@ def _mark_failed(session, task, error_msg: str) -> None:
            pass


-@celery.task(
-    name="backend.app.tasks.import_file.import_media_file",
-    bind=True,
-    autoretry_for=(OperationalError, DBAPIError, OSError),
-    retry_backoff=5,
-    retry_backoff_max=60,
-    retry_jitter=True,
-    max_retries=3,
-    soft_time_limit=300,
-    time_limit=360,
-)
-def import_media_file(self, import_task_id: int) -> dict:
-    """Returns a dict so the eager-mode tests can assert without DB.
-
-    Decorator notes:
-      - autoretry_for: transient DB / filesystem errors retry with
-        exponential backoff (5s base, jitter, max 3 attempts). On final
-        give-up the task raises and acks_late=True (set globally on the
-        Celery app) does NOT redeliver — the recovery sweep catches the
-        row instead.
-      - soft_time_limit (300s) raises SoftTimeLimitExceeded in this
-        process so the task can mark its row failed before being killed.
-      - time_limit (360s) is the hard cap; SIGKILL if the soft signal
-        was swallowed.
+def _run_import_task(import_task_id: int) -> dict:
+    """Shared body for import_media_file + import_archive_file. The two
+    tasks differ ONLY in their Celery time limits (a single media file
+    is sub-second; an archive runs the full per-member pipeline inline
+    for every member and can take many minutes). Both flip the row to
+    'processing', dispatch to `_do_import`, and honor the
+    flip-to-terminal resilience contract.
    """
    SessionLocal = _sync_session_factory()
    with SessionLocal() as session:
@@ -103,24 +86,88 @@ def import_media_file(self, import_task_id: int) -> dict:
        try:
            return _do_import(session, task, import_task_id)
        except SoftTimeLimitExceeded:
-            _mark_failed(session, task, "soft_time_limit exceeded (>300s)")
+            _mark_failed(session, task, "soft_time_limit exceeded")
            raise
        except (OperationalError, DBAPIError, OSError):
            # Retryable per the decorator; do NOT mark failed (let
            # autoretry have a clean go at it). If autoretry exhausts,
            # the row stays 'processing' and the maintenance sweep
-            # flips it within 5 min.
+            # flips it.
            raise
        except Exception as exc:  # noqa: BLE001 — pipeline crash, mark + re-raise
            _mark_failed(session, task, f"{type(exc).__name__}: {exc}")
            raise


+@celery.task(
+    name="backend.app.tasks.import_file.import_media_file",
+    bind=True,
+    autoretry_for=(OperationalError, DBAPIError, OSError),
+    retry_backoff=5,
+    retry_backoff_max=60,
+    retry_jitter=True,
+    max_retries=3,
+    soft_time_limit=300,
+    time_limit=360,
+)
+def import_media_file(self, import_task_id: int) -> dict:
+    """Import ONE media file (or non-media → PostAttachment). Sub-second
+    for the common case; the tight 5-min soft limit keeps a genuinely
+    stuck single-file import detectable fast.
+
+    Decorator notes:
+      - autoretry_for: transient DB / filesystem errors retry with
+        exponential backoff (5s base, jitter, max 3 attempts). On final
+        give-up the task raises and acks_late=True (set globally on the
+        Celery app) does NOT redeliver — the recovery sweep catches the
+        row instead.
+      - soft_time_limit (300s) raises SoftTimeLimitExceeded in-process
+        so the task can mark its row failed before being killed.
+      - time_limit (360s) is the hard SIGKILL cap.
+    """
+    return _run_import_task(import_task_id)
+
+
+@celery.task(
+    name="backend.app.tasks.import_file.import_archive_file",
+    bind=True,
+    autoretry_for=(OperationalError, DBAPIError, OSError),
+    retry_backoff=5,
+    retry_backoff_max=60,
+    retry_jitter=True,
+    max_retries=3,
+    # Archives run the full per-member pipeline (sha256 + pHash + dedup
+    # query + copy + provenance) for EVERY media member inline, under a
+    # single task budget. A multi-hundred-member archive blows the
+    # 5-min media limit. soft=30min / hard=35min sizes for a large
+    # archive. Operator-flagged 2026-05-28 (target 1645019 hit the old
+    # shared 300s soft limit). The recovery sweep gives this task its
+    # own 40-min threshold via maintenance.TASK_STUCK_THRESHOLD_MINUTES
+    # so it isn't preempted while legitimately grinding through members.
+    soft_time_limit=1800,
+    time_limit=2100,
+)
+def import_archive_file(self, import_task_id: int) -> dict:
+    """Import an archive: extract + run the per-member media pipeline for
+    every member inline, then preserve the archive as a PostAttachment.
+    Same body as import_media_file (dispatch is by file kind inside
+    Importer.import_one); split out purely for the larger time budget."""
+    return _run_import_task(import_task_id)
+
+
+def enqueue_import(task_id: int, task_type: str) -> None:
+    """Route an ImportTask to the right Celery task by its task_type.
+    Single source of truth for the media-vs-archive dispatch so the
+    scan, retry, and recovery-requeue paths stay in sync."""
+    if task_type == "archive":
+        import_archive_file.delay(task_id)
+    else:
+        import_media_file.delay(task_id)
+
+
 def _do_import(session, task, import_task_id: int) -> dict:
    """Actual work, called from inside the resilience wrapper."""
-    settings = session.execute(
-        select(ImportSettings).where(ImportSettings.id == 1)
-    ).scalar_one()
+    settings = ImportSettings.load_sync(session)
    import_root = Path(settings.import_scan_path)
    batch = session.get(ImportBatch, task.batch_id)
    deep = bool(batch and batch.scan_mode == "deep")
@@ -1,22 +1,56 @@
 """Periodic maintenance: recover stuck import tasks, garbage-collect old finished tasks."""

 import logging
+import os
 import subprocess
 from datetime import UTC, datetime, timedelta
 from pathlib import Path

 from PIL import Image
-from sqlalchemy import delete, select, update
+from sqlalchemy import Integer, and_, cast, delete, func, or_, select, update

 from ..celery_app import celery
-from ..models import DownloadEvent, ImageRecord, ImportSettings, ImportTask, TaskRun
+from ..models import (
+    BackupRun,
+    DownloadEvent,
+    ImageRecord,
+    ImportBatch,
+    ImportSettings,
+    ImportTask,
+    LibraryAuditRun,
+    Source,
+    TaskRun,
+)
 from ..utils.phash import compute_phash
 from ._sync_engine import sync_session_factory as _sync_session_factory

 log = logging.getLogger(__name__)

 STUCK_THRESHOLD_MINUTES = 5
+# Archive ImportTasks run the per-member pipeline inline for every
+# member (import_archive_file: soft=30min/hard=35min). The ImportTask
+# 'processing' recovery sweep must give them a longer threshold or it
+# re-queues a legitimately-running archive mid-import (double-process).
+# 40 min = 5-min buffer past the archive task's hard kill.
+# Operator-flagged 2026-05-28 (target 1645019, a big archive).
+ARCHIVE_STUCK_THRESHOLD_MINUTES = 40
+
+# Poison-pill cap. After being recovered (re-queued from a stuck
+# 'processing' state) MAX_RECOVERY_ATTEMPTS-1 times, the next sweep
+# marks the row 'failed' instead of looping. 3 = two recoveries then
+# give up. A row reaches this only if it leaves NO terminal flip each
+# run — i.e. it hard-crashes the worker (OOM/segfault/SIGKILL), the
+# signature of a corrupt or oversized input. Caught exceptions already
+# flip to terminal 'failed' and never enter this loop.
+MAX_RECOVERY_ATTEMPTS = 3
 ORPHAN_PENDING_THRESHOLD_MINUTES = 30
+
+# DownloadEvent (pending|running) recovery threshold. download_source has
+# time_limit=1200s (20 min); 30 min is 10 min past that, so a legitimately-
+# running task is never killed by the sweep. Operator-confirmed 2026-05-29
+# after 43 sources stranded at "last check never" by the in-flight guard.
+DOWNLOAD_STALL_THRESHOLD_MINUTES = 30
+
 OLD_TASK_DAYS = 7
 PHASH_PAGE = 500
 VERIFY_PAGE = 200
@@ -24,17 +58,78 @@ FFPROBE_TIMEOUT_SECONDS = 10
 TASK_RUN_KEEP_OK_SECONDS = 24 * 3600       # 24 h
 TASK_RUN_KEEP_FAILURE_SECONDS = 7 * 24 * 3600  # 7 days

+# Audit 2026-06-02: per-entity recovery sweep thresholds. Each must be
+# > the entity's longest legitimate runtime (its task's time_limit + a
+# small buffer) so the sweep never flags in-flight work.
+#
+# Backups: images backup has time_limit=23400s (6.5h). 7h covers it
+# with a 30-min buffer; db backup at 12 min hard limit fits trivially.
+BACKUP_STALL_THRESHOLD_MINUTES = 7 * 60
+# Library audit: scan_library_for_rule has time_limit=7500s (2h5m).
+# 2h15m gives a 10-min buffer.
+LIBRARY_AUDIT_STALL_THRESHOLD_MINUTES = 135
+# Import batches finalize only after every child ImportTask hits a
+# terminal state. The recovery sweep targets the case where every
+# task is done but the batch never got its closing UPDATE
+# (orchestrator crashed at the wrong instant). 2h is well past any
+# realistic single-batch import.
+IMPORT_BATCH_STALL_THRESHOLD_MINUTES = 120
+
+# Retention windows (terminal rows older than these get deleted by
+# the daily prune sweeps). 30 days = operator-flagged "useful for
+# triage for a few weeks, then noise."
+LIBRARY_AUDIT_KEEP_DAYS = 30
+IMPORT_BATCH_KEEP_DAYS = 30
+
+# Overrides for recover_stalled_task_runs (the TaskRun 'running' sweep).
+# Tasks/queues that legitimately run longer than the default 5-min
+# threshold need their own larger value, else the sweep marks in-flight
+# work 'error' before it finishes. Each value MUST be ≥ the relevant
+# task.time_limit + a small buffer. task_name overrides take precedence
+# over queue overrides.
+#
+# ml queue: tag_and_embed video branch (≈20 GPU ops); time_limit=1200.
+# import_archive_file: shares the 'import' queue with the fast
+#   single-file import_media_file, so it needs a task-name override
+#   (the import queue itself stays at the 5-min default for single
+#   files); time_limit=2100.
+QUEUE_STUCK_THRESHOLD_MINUTES: dict[str, int] = {
+    "ml": 25,
+    # Audit 2026-06-02 — maintenance/scan queues run tasks that
+    # legitimately exceed the 5-min default (verify_integrity at 70m
+    # hard, scan_directory at 70m hard, apply_allowlist_tags /
+    # recompute_centroids / backfill_phash at 35m hard). 75 min lives
+    # above the longest of those and the per-task overrides below
+    # cover the outliers (backups, library audit).
+    "maintenance": 75,
+    "scan": 75,
+}
+TASK_STUCK_THRESHOLD_MINUTES: dict[str, int] = {
+    "backend.app.tasks.import_file.import_archive_file": 40,
+    # Backup images runs hours, not minutes (6.5h hard limit). The
+    # task-name override beats the queue's 75-min default so a
+    # legitimately-running backup isn't flagged.
+    "backend.app.tasks.backup.backup_images_task": 420,
+    "backend.app.tasks.backup.restore_images_task": 420,
+    # Library audit scans the full library — 2h hard limit.
+    "backend.app.tasks.library_audit.scan_library_for_rule": 130,
+}
+

@celery.task(name="backend.app.tasks.maintenance.recover_interrupted_tasks")
 def recover_interrupted_tasks() -> int:
    """Recover stuck ImportTask rows. Two distinct stuck states:

-    1. 'processing' > 5 min — worker crash mid-import. Re-queue via
-       .delay() and let the import retry. Was 30 min historically;
-       tightened 2026-05-24 after operator hit a 2224-row zombie pile.
-       import_media_file is sub-second for the vast majority of files and
-       capped at the per-task soft_time_limit (5 min), so anything still
-       'processing' after that window is a confirmed crash.
+    1. 'processing' too long — worker crash mid-import. Re-queue via
+       enqueue_import (routing media vs archive) and let the import
+       retry. Threshold is task-type-aware: media files are sub-second
+       and capped at the 5-min soft limit, so STUCK_THRESHOLD_MINUTES
+       (5) means a confirmed crash; archives run the per-member
+       pipeline inline (import_archive_file, 35-min hard limit) so they
+       get ARCHIVE_STUCK_THRESHOLD_MINUTES (40) to avoid re-queueing a
+       still-running archive. (Media was tightened from 30 min to 5
+       2026-05-24 after a 2224-row zombie pile; archive split out
+       2026-05-28.)

    2. 'pending' or 'queued' > 30 min — enqueue-phase crash. scan_directory
       creates rows with status='pending' (commit), then in a second pass
@@ -51,7 +146,8 @@ def recover_interrupted_tasks() -> int:
    """
    SessionLocal = _sync_session_factory()
    now = datetime.now(UTC)
-    processing_cutoff = now - timedelta(minutes=STUCK_THRESHOLD_MINUTES)
+    media_cutoff = now - timedelta(minutes=STUCK_THRESHOLD_MINUTES)
+    archive_cutoff = now - timedelta(minutes=ARCHIVE_STUCK_THRESHOLD_MINUTES)
    orphan_cutoff = now - timedelta(minutes=ORPHAN_PENDING_THRESHOLD_MINUTES)
    with SessionLocal() as session:
        # Both sweeps used to be SELECT ids → UPDATE WHERE id IN (...) which
@@ -59,20 +155,67 @@ def recover_interrupted_tasks() -> int:
        # tens of thousands of rows (operator hit it 2026-05-26 after the
        # /import deep scan piled up orphans). Folding the SELECT into the
        # UPDATE eliminates the IN-list entirely. RETURNING gives us back
-        # exactly the ids that flipped so the stuck sweep can still
-        # .delay() each one.
-        stuck_result = session.execute(
+        # exactly the (id, task_type) pairs that flipped so the requeue
+        # can route media vs archive correctly.
+        #
+        # Media + archive get separate cutoffs: a single media file is
+        # sub-second so 5 min means crash; an archive runs the per-member
+        # pipeline inline and can legitimately take up to its 35-min hard
+        # limit, so it gets ARCHIVE_STUCK_THRESHOLD_MINUTES (40) to avoid
+        # re-queueing a still-running archive.
+        stuck_predicate = and_(
+            ImportTask.status == "processing",
+            or_(
+                and_(ImportTask.task_type != "archive",
+                     ImportTask.started_at < media_cutoff),
+                and_(ImportTask.task_type == "archive",
+                     ImportTask.started_at < archive_cutoff),
+            ),
+        )
+
+        # POISON-PILL CIRCUIT BREAKER (Layer 1, 2026-05-28). A row that
+        # leaves no terminal flip (hard worker crash: OOM/segfault/SIGKILL
+        # on a corrupt or oversized input) gets re-queued by this sweep —
+        # and would loop forever, re-crashing the worker each pass,
+        # without a cap. Once a row has already been recovered
+        # MAX_RECOVERY_ATTEMPTS-1 times, stop re-queueing it and mark it
+        # 'failed' with a diagnostic so the operator can find + replace
+        # the offending file. This UPDATE runs FIRST so the rows it
+        # claims drop out of 'processing' before the re-queue pass.
+        poison_result = session.execute(
            update(ImportTask)
-            .where(ImportTask.status == "processing")
-            .where(ImportTask.started_at < processing_cutoff)
+            .where(stuck_predicate)
+            .where(ImportTask.recovery_count >= MAX_RECOVERY_ATTEMPTS - 1)
            .values(
-                status="queued",
-                started_at=None,
-                error="recovered from stuck state",
+                status="failed",
+                finished_at=now,
+                error=(
+                    f"crashed or stalled the worker {MAX_RECOVERY_ATTEMPTS} "
+                    f"times without completing — likely a corrupt or "
+                    f"oversized input. Not re-queued. Inspect/replace the "
+                    f"file, then retry via /api/import/retry-failed."
+                ),
            )
            .returning(ImportTask.id)
        )
-        stuck_ids = [row[0] for row in stuck_result.all()]
+        poison_ids = [r[0] for r in poison_result.all()]
+
+        # Re-queue the remaining stuck rows (under the cap) and bump
+        # their recovery_count. RETURNING (id, task_type) so the requeue
+        # routes media vs archive correctly.
+        stuck_result = session.execute(
+            update(ImportTask)
+            .where(stuck_predicate)
+            .where(ImportTask.recovery_count < MAX_RECOVERY_ATTEMPTS - 1)
+            .values(
+                status="queued",
+                started_at=None,
+                recovery_count=ImportTask.recovery_count + 1,
+                error="recovered from stuck state",
+            )
+            .returning(ImportTask.id, ImportTask.task_type)
+        )
+        stuck = stuck_result.all()

        orphan_result = session.execute(
            update(ImportTask)
@@ -80,6 +223,11 @@ def recover_interrupted_tasks() -> int:
            .where(ImportTask.created_at < orphan_cutoff)
            .values(
                status="failed",
+                # Without finished_at, cleanup_old_tasks (`WHERE
+                # finished_at < cutoff`) never reaps these rows —
+                # orphan-swept rows would become permanent table
+                # tenants. Audit 2026-06-02.
+                finished_at=now,
                error=(
                    "orphan pending/queued swept by recover_interrupted_tasks "
                    "(scanner likely crashed mid-enqueue); retry via "
@@ -91,12 +239,34 @@ def recover_interrupted_tasks() -> int:

        session.commit()

-        if stuck_ids:
-            from .import_file import import_media_file
-            for tid in stuck_ids:
-                import_media_file.delay(tid)
+        if stuck:
+            from .import_file import enqueue_import
+            for tid, task_type in stuck:
+                enqueue_import(tid, task_type)

-        return len(stuck_ids) + orphan_count
+        # Layer-2 auto re-download (env-gated, default OFF). For each
+        # poison-pill row that resolves to a pollable Source, delete the
+        # bad file and trigger ONE source re-check to fetch a fresh
+        # copy. Bounded by ImportTask.refetched so source-side
+        # corruption can't loop. The 'failed' row stays as history; the
+        # re-downloaded file re-imports as a fresh task on the next scan.
+        if poison_ids and os.environ.get("FC_AUTO_REFETCH_CORRUPT", "0") == "1":
+            from ..models import ImportSettings
+            from ..services.refetch_service import attempt_refetch
+            import_root = Path(session.execute(
+                select(ImportSettings.import_scan_path)
+                .where(ImportSettings.id == 1)
+            ).scalar_one())
+            for pid in poison_ids:
+                ptask = session.get(ImportTask, pid)
+                if ptask is None:
+                    continue
+                try:
+                    attempt_refetch(session, ptask, import_root)
+                except Exception as exc:  # noqa: BLE001 — best-effort
+                    log.warning("auto-refetch failed for task %s: %s", pid, exc)
+
+        return len(stuck) + len(poison_ids) + orphan_count


@celery.task(name="backend.app.tasks.maintenance.cleanup_old_tasks")
@@ -121,18 +291,29 @@ def cleanup_old_tasks() -> int:

@celery.task(name="backend.app.tasks.maintenance.recover_stalled_task_runs")
 def recover_stalled_task_runs() -> int:
-    """Flip task_run rows stuck in 'running' for >STUCK_THRESHOLD_MINUTES
-    to 'error'. FC-3i.
+    """Flip task_run rows stuck in 'running' past their queue-specific
+    threshold to 'error'. FC-3i.

    A row gets stuck when the worker dies without emitting
    task_postrun / task_failure (e.g. OOM, container restart between
-    signals, signal handler raised+logged). Shares the 5-min threshold
-    with recover_interrupted_tasks for consistency.
+    signals, signal handler raised+logged). The default 5-min threshold
+    fits short-lived queues (import/thumbnail/download); queues that
+    legitimately run longer tasks (ml-video, deep scans) get their
+    own larger threshold via QUEUE_STUCK_THRESHOLD_MINUTES so the
+    sweep doesn't preempt them.
+
+    Runs once per distinct threshold value: each pass updates rows
+    whose queue maps to that threshold.
    """
    SessionLocal = _sync_session_factory()
-    cutoff = datetime.now(UTC) - timedelta(minutes=STUCK_THRESHOLD_MINUTES)
-    with SessionLocal() as session:
-        result = session.execute(
+    now = datetime.now(UTC)
+    override_tasks = set(TASK_STUCK_THRESHOLD_MINUTES.keys())
+    override_queues = set(QUEUE_STUCK_THRESHOLD_MINUTES.keys())
+    total = 0
+
+    def _flag(minutes, *extra_where):
+        cutoff = now - timedelta(minutes=minutes)
+        stmt = (
            update(TaskRun)
            .where(TaskRun.status == "running")
            .where(TaskRun.started_at < cutoff)
@@ -140,14 +321,50 @@ def recover_stalled_task_runs() -> int:
                status="error",
                error_type="RecoverySweep",
                error_message=(
-                    f"no completion signal received within "
-                    f"{STUCK_THRESHOLD_MINUTES} min"
+                    f"no completion signal received within {minutes} min"
+                ),
+                finished_at=now,
+                # Matches celery_signals.finalize's
+                # int((now - started_at).total_seconds() * 1000)
+                # — sweep-closed rows now carry duration like
+                # normally-finalized rows. Audit 2026-06-02.
+                duration_ms=cast(
+                    func.extract("epoch", now - TaskRun.started_at) * 1000,
+                    Integer,
                ),
-                finished_at=datetime.now(UTC),
            )
        )
+        for w in extra_where:
+            stmt = stmt.where(w)
+        return session.execute(stmt).rowcount or 0
+
+    with SessionLocal() as session:
+        # Precedence: task_name override → queue override → default.
+        # Each pass excludes rows claimed by a higher-precedence pass so
+        # every row is touched at most once.
+
+        # 1. Per-task-name overrides (e.g. import_archive_file, which
+        #    shares the 'import' queue with fast single-file imports).
+        for task_name, minutes in TASK_STUCK_THRESHOLD_MINUTES.items():
+            total += _flag(minutes, TaskRun.task_name == task_name)
+
+        # 2. Per-queue overrides, excluding the override task-names.
+        for queue, minutes in QUEUE_STUCK_THRESHOLD_MINUTES.items():
+            wheres = [TaskRun.queue == queue]
+            if override_tasks:
+                wheres.append(TaskRun.task_name.notin_(override_tasks))
+            total += _flag(minutes, *wheres)
+
+        # 3. Default — everything not claimed above.
+        default_wheres = []
+        if override_queues:
+            default_wheres.append(TaskRun.queue.notin_(override_queues))
+        if override_tasks:
+            default_wheres.append(TaskRun.task_name.notin_(override_tasks))
+        total += _flag(STUCK_THRESHOLD_MINUTES, *default_wheres)
+
        session.commit()
-        return result.rowcount or 0
+        return total


@celery.task(name="backend.app.tasks.maintenance.prune_task_runs")
@@ -184,7 +401,12 @@ def prune_task_runs() -> dict:
        return {"ok_deleted": ok_deleted, "failures_deleted": fail_deleted}


-@celery.task(name="backend.app.tasks.maintenance.backfill_phash")
+@celery.task(
+    name="backend.app.tasks.maintenance.backfill_phash",
+    # Audit 2026-06-02 — keyset-paginated phash recompute over the whole
+    # library; legitimately runs >5 min on large libraries.
+    soft_time_limit=1800, time_limit=2100,
+)
 def backfill_phash() -> int:
    """Recompute phash for stored images that have none (imported before
    FC-2d-i+ii). Keyset-paginated by id (restart-safe), NULL-only fill,
@@ -262,7 +484,13 @@ def _verify_one(path: Path, expected_sha: str, mime: str, sha_fn) -> str:
        return "failed_verification"


-@celery.task(name="backend.app.tasks.maintenance.verify_integrity")
+@celery.task(
+    name="backend.app.tasks.maintenance.verify_integrity",
+    # Audit 2026-06-02 — full library sha256 + decode probe; on 100k-image
+    # libraries this runs an hour or more. Match the maintenance queue's
+    # recovery threshold (75 min) with 30s buffer below.
+    soft_time_limit=3600, time_limit=4200,
+)
 def verify_integrity() -> int:
    """Verify every ImageRecord file: sha256 recompute + decode/probe
    (PIL for images; ffprobe for videos). Writes integrity_status
@@ -299,6 +527,215 @@ def verify_integrity() -> int:
    return total


+@celery.task(name="backend.app.tasks.maintenance.recover_stalled_download_events")
+def recover_stalled_download_events() -> int:
+    """Recover DownloadEvent rows stuck pending/running past the worker hard kill.
+
+    The scan tick (scheduler_service.select_due_sources →
+    tasks.scan._tick_due_sources_async) inserts DownloadEvent(status='pending')
+    and fires download_source.delay(). If that task dies before finalizing the
+    event — worker OOM/SIGKILL, lost task, or a gallery-dl that didn't unwind
+    on the 1200s hard time_limit — the event stays in-flight forever. The next
+    tick then skips that source because of the in-flight guard (scan.py:168)
+    and Source.last_checked_at never updates; the operator sees "last check
+    never" in the Subscriptions health column, permanently.
+
+    This sweep flips matching events to 'error', stamps each affected Source's
+    last_checked_at + last_error and bumps consecutive_failures (once per
+    source, not per event — backoff is exponential on that count so an N-event
+    bump would inflate the next interval by 2^N for no reason). The source
+    becomes re-queueable on the next tick and the health dot goes amber.
+
+    Operator-confirmed 2026-05-29 (43-row strand pile in production).
+    """
+    SessionLocal = _sync_session_factory()
+    now = datetime.now(UTC)
+    cutoff = now - timedelta(minutes=DOWNLOAD_STALL_THRESHOLD_MINUTES)
+    msg = "stranded by recovery sweep (no terminal status after time_limit)"
+    with SessionLocal() as session:
+        # UPDATE...RETURNING the source_ids in one round trip — keeps us off
+        # the psycopg 65535-param ceiling that SELECT-then-UPDATE-WHERE-IN
+        # would hit on a large strand pile.
+        result = session.execute(
+            update(DownloadEvent)
+            .where(DownloadEvent.status.in_(["pending", "running"]))
+            .where(DownloadEvent.started_at < cutoff)
+            .values(status="error", finished_at=now, error=msg)
+            .returning(DownloadEvent.source_id)
+        )
+        returned = result.all()
+        if not returned:
+            session.commit()
+            return 0
+        events_recovered = len(returned)
+        source_ids = list({row.source_id for row in returned})
+        session.execute(
+            update(Source)
+            .where(Source.id.in_(source_ids))
+            .values(
+                consecutive_failures=Source.consecutive_failures + 1,
+                last_error=msg,
+                last_checked_at=now,
+            )
+        )
+        session.commit()
+        log.info(
+            "recover_stalled_download_events: recovered %d events across %d sources",
+            events_recovered, len(source_ids),
+        )
+        return events_recovered
+
+
+@celery.task(name="backend.app.tasks.maintenance.recover_stalled_backup_runs")
+def recover_stalled_backup_runs() -> int:
+    """Flip BackupRun rows stuck in running/restoring past the hard limit
+    to error. Audit 2026-06-02.
+
+    prune_backups (FC-3h) used to claim the FC-3i task_run sweep handled
+    these — but that sweep only flips TaskRun rows, not the BackupRun
+    artifact rows. A SIGKILL'd backup left BackupRun stuck forever
+    (dashboard showed phantom in-flight backups, keep_last_n offset
+    arithmetic skewed because zombies sat outside the ok/error window).
+    """
+    SessionLocal = _sync_session_factory()
+    now = datetime.now(UTC)
+    cutoff = now - timedelta(minutes=BACKUP_STALL_THRESHOLD_MINUTES)
+    msg = (
+        f"stranded by recovery sweep (no terminal status after "
+        f"{BACKUP_STALL_THRESHOLD_MINUTES // 60}h)"
+    )
+    with SessionLocal() as session:
+        result = session.execute(
+            update(BackupRun)
+            .where(BackupRun.status.in_(["running", "restoring"]))
+            .where(BackupRun.started_at < cutoff)
+            .values(status="error", finished_at=now, error=msg)
+        )
+        session.commit()
+        recovered = result.rowcount or 0
+        if recovered:
+            log.info("recover_stalled_backup_runs: recovered %d rows", recovered)
+        return recovered
+
+
+@celery.task(name="backend.app.tasks.maintenance.recover_stalled_library_audit_runs")
+def recover_stalled_library_audit_runs() -> int:
+    """Flip LibraryAuditRun rows stuck in running past the hard limit
+    to error. Audit 2026-06-02.
+
+    LibraryAuditRun.status='running' was protected by an exclusive
+    guard in start_audit_run — a SIGKILL'd run would block all future
+    audits until manual DB surgery. (The guard is now age-aware, but
+    this sweep is what makes that work in practice.)
+    """
+    SessionLocal = _sync_session_factory()
+    now = datetime.now(UTC)
+    cutoff = now - timedelta(minutes=LIBRARY_AUDIT_STALL_THRESHOLD_MINUTES)
+    msg = (
+        f"stranded by recovery sweep (no terminal status after "
+        f"{LIBRARY_AUDIT_STALL_THRESHOLD_MINUTES} min)"
+    )
+    with SessionLocal() as session:
+        result = session.execute(
+            update(LibraryAuditRun)
+            .where(LibraryAuditRun.status == "running")
+            .where(LibraryAuditRun.started_at < cutoff)
+            .values(status="error", finished_at=now, error=msg)
+        )
+        session.commit()
+        recovered = result.rowcount or 0
+        if recovered:
+            log.info(
+                "recover_stalled_library_audit_runs: recovered %d rows", recovered,
+            )
+        return recovered
+
+
+@celery.task(name="backend.app.tasks.maintenance.recover_stalled_import_batches")
+def recover_stalled_import_batches() -> int:
+    """Finalize ImportBatch rows stuck in running past the hard limit
+    when NO outstanding ImportTask remains. Audit 2026-06-02.
+
+    A batch row finalizes only after every child task hits a terminal
+    state. The orphan case: scanner crashed between the last task's
+    completion and the batch's closing UPDATE. The
+    `/api/import/status` route then surfaces the batch as 'active'
+    indefinitely while `/api/system/stats` (which uses the same
+    EXISTS predicate we apply below) correctly returns null.
+    """
+    SessionLocal = _sync_session_factory()
+    now = datetime.now(UTC)
+    cutoff = now - timedelta(minutes=IMPORT_BATCH_STALL_THRESHOLD_MINUTES)
+    with SessionLocal() as session:
+        # Batches still 'running' past the cutoff whose tasks are all
+        # terminal — there's no outstanding work, so flip the batch
+        # too. Mirrors the EXISTS predicate the active-batch surfaces use.
+        result = session.execute(
+            update(ImportBatch)
+            .where(ImportBatch.status == "running")
+            .where(ImportBatch.started_at < cutoff)
+            .where(
+                ~select(ImportTask.id)
+                .where(
+                    ImportTask.batch_id == ImportBatch.id,
+                    ImportTask.status.in_(["pending", "queued", "processing"]),
+                )
+                .exists()
+            )
+            .values(status="complete", finished_at=now)
+        )
+        session.commit()
+        recovered = result.rowcount or 0
+        if recovered:
+            log.info(
+                "recover_stalled_import_batches: finalized %d zombie batches",
+                recovered,
+            )
+        return recovered
+
+
+@celery.task(name="backend.app.tasks.maintenance.prune_library_audit_runs")
+def prune_library_audit_runs() -> int:
+    """Daily retention: delete terminal LibraryAuditRun rows older than
+    LIBRARY_AUDIT_KEEP_DAYS. Never touches 'running'. Audit 2026-06-02.
+
+    Audit rows carry matched_ids JSONB blobs that can hold tens of
+    thousands of ids; without retention these accumulate.
+    """
+    SessionLocal = _sync_session_factory()
+    cutoff = datetime.now(UTC) - timedelta(days=LIBRARY_AUDIT_KEEP_DAYS)
+    with SessionLocal() as session:
+        result = session.execute(
+            delete(LibraryAuditRun)
+            .where(LibraryAuditRun.status.in_(["ready", "applied", "cancelled", "error"]))
+            .where(LibraryAuditRun.finished_at < cutoff)
+        )
+        session.commit()
+        return result.rowcount or 0
+
+
+@celery.task(name="backend.app.tasks.maintenance.prune_import_batches")
+def prune_import_batches() -> int:
+    """Daily retention: delete terminal ImportBatch rows older than
+    IMPORT_BATCH_KEEP_DAYS. Cascade-deletes child ImportTask rows via
+    the model relationship. Never touches 'running'. Audit 2026-06-02.
+    """
+    SessionLocal = _sync_session_factory()
+    cutoff = datetime.now(UTC) - timedelta(days=IMPORT_BATCH_KEEP_DAYS)
+    with SessionLocal() as session:
+        # ORM-level delete here (not Core delete) so the
+        # ImportBatch->tasks cascade fires; Core delete would skip it.
+        old_batches = session.execute(
+            select(ImportBatch)
+            .where(ImportBatch.status.in_(["complete", "cancelled"]))
+            .where(ImportBatch.finished_at < cutoff)
+        ).scalars().all()
+        for batch in old_batches:
+            session.delete(batch)
+        session.commit()
+        return len(old_batches)
+
+
@celery.task(name="backend.app.tasks.maintenance.cleanup_old_download_events")
 def cleanup_old_download_events() -> int:
    """FC-3d: delete terminal DownloadEvent rows older than the configured
@@ -311,9 +748,7 @@ def cleanup_old_download_events() -> int:
    """
    SessionLocal = _sync_session_factory()
    with SessionLocal() as session:
-        settings = session.execute(
-            select(ImportSettings).where(ImportSettings.id == 1)
-        ).scalar_one()
+        settings = ImportSettings.load_sync(session)
        retention_days = settings.download_event_retention_days
        cutoff = datetime.now(UTC) - timedelta(days=retention_days)
        result = session.execute(
@@ -1,175 +0,0 @@
-"""FC-5 run_migration Celery task.
-
-Dispatches to the right migrator based on `kind`. Updates MigrationRun
-row's status/counts/finished_at as it runs. Failures set status='error'
-with the error message preserved.
-
-kinds: gs_ingest, ir_ingest, tag_apply, ml_queue, verify, cleanup
-(backup + rollback retired 2026-05-24 → see /api/system/backup/*)
-"""
-from __future__ import annotations
-
-import asyncio
-import logging
-from datetime import UTC, datetime
-from pathlib import Path
-
-from sqlalchemy import select
-from sqlalchemy.ext.asyncio import AsyncSession, async_sessionmaker, create_async_engine
-
-from ..celery_app import celery
-from ..config import get_config
-from ..models import MigrationRun
-from ..services.credential_crypto import CredentialCrypto
-from ..services.migrators import cleanup as cleanup_mod
-from ..services.migrators import gs_ingest, ir_ingest, ml_queue, tag_apply, verify
-
-log = logging.getLogger(__name__)
-
-IMAGES_ROOT = Path("/images")
-_KEY_PATH = IMAGES_ROOT / "secrets" / "credential_key.b64"
-
-
-def _async_session_factory():
-    cfg = get_config()
-    engine = create_async_engine(cfg.database_url, future=True, pool_pre_ping=True)
-    return async_sessionmaker(engine, class_=AsyncSession, expire_on_commit=False), engine
-
-
-async def _update_run(
-    db: AsyncSession, run_id: int, *,
-    status: str | None = None, counts: dict | None = None,
-    error: str | None = None, finished_at: datetime | None = None,
-    metadata_patch: dict | None = None,
-) -> None:
-    run = (await db.execute(
-        select(MigrationRun).where(MigrationRun.id == run_id)
-    )).scalar_one()
-    if status is not None:
-        run.status = status
-    if counts is not None:
-        run.counts = counts
-    if error is not None:
-        run.error = error
-    if finished_at is not None:
-        run.finished_at = finished_at
-    if metadata_patch:
-        run.metadata_ = {**(run.metadata_ or {}), **metadata_patch}
-    await db.commit()
-
-
-async def _run_async(run_id: int, kind: str, params: dict) -> dict:
-    factory, engine = _async_session_factory()
-    try:
-        async with factory() as db:
-            await _update_run(db, run_id, status="running")
-            try:
-                if kind in ("backup", "rollback"):
-                    raise ValueError(
-                        f"kind {kind!r} retired in FC-3h; "
-                        "use /api/system/backup/* instead"
-                    )
-
-                elif kind == "gs_ingest":
-                    fc_crypto = CredentialCrypto(_KEY_PATH)
-                    counts = await gs_ingest.migrate_async(
-                        db, data=params["data"],
-                        fc_crypto=fc_crypto,
-                        dry_run=params.get("dry_run", False),
-                    )
-                    await _update_run(
-                        db, run_id, status="ok", counts=counts,
-                        finished_at=datetime.now(UTC),
-                    )
-                    return counts
-
-                elif kind == "ir_ingest":
-                    counts = await ir_ingest.migrate_async(
-                        db, data=params["data"],
-                        images_root=IMAGES_ROOT,
-                        dry_run=params.get("dry_run", False),
-                    )
-                    await _update_run(
-                        db, run_id, status="ok", counts=counts,
-                        finished_at=datetime.now(UTC),
-                    )
-                    return counts
-
-                elif kind == "tag_apply":
-                    result = await tag_apply.apply_async(
-                        db, images_root=IMAGES_ROOT,
-                        dry_run=params.get("dry_run", False),
-                    )
-                    await _update_run(
-                        db, run_id, status="ok",
-                        counts=result["counts"],
-                        finished_at=datetime.now(UTC),
-                        metadata_patch={"unmatched": result["unmatched"]},
-                    )
-                    return result
-
-                elif kind == "ml_queue":
-                    count = await ml_queue.queue_all_unprocessed_async(db)
-                    await _update_run(
-                        db, run_id, status="ok",
-                        counts={"rows_processed": count, "rows_inserted": 0,
-                                "rows_skipped": 0, "files_copied": 0,
-                                "bytes_copied": 0, "conflicts": 0},
-                        finished_at=datetime.now(UTC),
-                    )
-                    return {"queued": count}
-
-                elif kind == "verify":
-                    checks = await verify.verify_async(db, expected=params.get("expected"))
-                    sample = await verify.verify_sha256_sample(
-                        db, sample_size=params.get("sample_size", 20),
-                    )
-                    await _update_run(
-                        db, run_id, status="ok",
-                        counts={"rows_processed": sample["sample_size"],
-                                "rows_inserted": 0, "rows_skipped": 0,
-                                "files_copied": 0, "bytes_copied": 0,
-                                "conflicts": sample["mismatched"] + sample["missing"]},
-                        finished_at=datetime.now(UTC),
-                        metadata_patch={"checks": checks, "sample": sample},
-                    )
-                    return {"checks": checks, "sample": sample}
-
-                elif kind == "cleanup":
-                    slug = params.get("slug")
-                    if not slug:
-                        raise ValueError("cleanup requires params.slug")
-                    result = await cleanup_mod.cleanup_artist_async(
-                        db, slug=slug, images_root=IMAGES_ROOT,
-                        dry_run=params.get("dry_run", False),
-                        source_path_prefix=params.get("source_path_prefix"),
-                    )
-                    await _update_run(
-                        db, run_id, status="ok",
-                        counts=result["counts"],
-                        finished_at=datetime.now(UTC),
-                        metadata_patch={
-                            "artist": result["artist"],
-                            "summary": result["summary"],
-                        },
-                    )
-                    return result
-
-                else:
-                    raise ValueError(f"unknown kind: {kind}")
-
-            except Exception as exc:
-                log.exception("migration kind=%s failed", kind)
-                await _update_run(
-                    db, run_id, status="error", error=str(exc),
-                    finished_at=datetime.now(UTC),
-                )
-                raise
-    finally:
-        await engine.dispose()
-
-
-@celery.task(name="backend.app.tasks.migration.run_migration", bind=True, acks_late=True)
-def run_migration(self, run_id: int, kind: str, params: dict) -> dict:
-    """FC-5: dispatch a migration kind. Updates MigrationRun row as it goes."""
-    return asyncio.run(_run_async(run_id, kind, params))
@@ -31,8 +31,15 @@ def _is_video(path: Path) -> bool:
    retry_backoff_max=60,
    retry_jitter=True,
    max_retries=3,
-    soft_time_limit=300,
-    time_limit=420,
+    # Sized for the video branch: sample 10 frames, run tagger +
+    # embedder on each (≈20 GPU ops vs 2 for an image). A loaded
+    # ml-worker can take 5-10 min on a long video; bumped from
+    # 5min/7min on 2026-05-28 after operator-flagged image 6288 (a
+    # .mp4) hit the recovery sweep at 5 min while still legitimately
+    # processing. Image runs return in seconds; the bump doesn't
+    # affect their UX.
+    soft_time_limit=900,   # 15 min
+    time_limit=1200,       # 20 min hard
 )
 def tag_and_embed(self, image_id: int) -> dict:
    """Run Camie + SigLIP on one image; store predictions + embedding;
@@ -64,6 +71,18 @@ def tag_and_embed(self, image_id: int) -> dict:
        embedder = get_embedder()

        if _is_video(src):
+            # Layer-3 isolation: ffprobe (a separate process) validates
+            # the container before we burn ~20 GPU ops sampling frames
+            # from it. A corrupt video that would crash the frame
+            # decoder is rejected cleanly here instead of taking down
+            # the ml-worker. Operator-flagged 2026-05-28.
+            from ..utils import safe_probe
+            vprobe = safe_probe.probe_video(src)
+            if not vprobe.ok:
+                return {
+                    "status": "bad_video", "image_id": image_id,
+                    "reason": vprobe.reason,
+                }
            frames = _sample_video_frames(
                src, int(os.environ.get("VIDEO_ML_FRAMES", "10"))
            )
@@ -193,7 +212,14 @@ def backfill(self) -> int:
    return enqueued


-@celery.task(name="backend.app.tasks.ml.apply_allowlist_tags", bind=True)
+@celery.task(
+    name="backend.app.tasks.ml.apply_allowlist_tags",
+    bind=True,
+    # Audit 2026-06-02 — the full-sweep mode (neither tag_id nor image_id)
+    # is O(images × allowlist) and legitimately runs >5 min on large
+    # libraries. Cap matches the maintenance queue's recovery threshold.
+    soft_time_limit=1800, time_limit=2100,
+)
 def apply_allowlist_tags(self, tag_id: int | None = None,
                         image_id: int | None = None) -> int:
    """Retroactively apply allowlisted tags.
@@ -322,7 +348,13 @@ def recompute_centroid(self, tag_id: int) -> bool:
    return asyncio.run(_run())


-@celery.task(name="backend.app.tasks.ml.recompute_centroids", bind=True)
+@celery.task(
+    name="backend.app.tasks.ml.recompute_centroids",
+    bind=True,
+    # Audit 2026-06-02 — drifted-centroid rebuild over potentially
+    # hundreds of tags.
+    soft_time_limit=1800, time_limit=2100,
+)
 def recompute_centroids(self) -> int:
    """Daily: find drifted centroids, enqueue recompute_centroid for each."""
    import asyncio
@@ -12,12 +12,12 @@ from datetime import UTC, datetime
 from pathlib import Path

 from sqlalchemy import select
-from sqlalchemy.ext.asyncio import AsyncSession, async_sessionmaker, create_async_engine

 from ..celery_app import celery
-from ..config import get_config
 from ..models import DownloadEvent, ImportBatch, ImportSettings, ImportTask
-from ..services.scheduler_service import select_due_sources
+from ..services.archive_extractor import is_archive
+from ..services.scheduler_service import record_tick, select_due_sources
+from ._async_session import async_session_factory
 from ._sync_engine import sync_session_factory as _sync_session_factory


@@ -35,7 +35,15 @@ def _iter_import_files(import_root: Path):
        yield entry


-@celery.task(name="backend.app.tasks.scan.scan_directory", bind=True)
+@celery.task(
+    name="backend.app.tasks.scan.scan_directory",
+    bind=True,
+    # Audit 2026-06-02 — large libraries make the scan legitimately long.
+    # Hard cap at 70 min so the corresponding QUEUE_STUCK_THRESHOLD_MINUTES
+    # ("scan") of 75 min always wins; soft limit gives the task a clean
+    # exit window before SIGKILL.
+    soft_time_limit=3600, time_limit=4200,
+)
 def scan_directory(self, triggered_by: str = "manual",
                   mode: str = "quick") -> int:
    """Walks the import root and creates ImportTasks. `mode` is 'quick'
@@ -44,9 +52,7 @@ def scan_directory(self, triggered_by: str = "manual",
    batch id."""
    SessionLocal = _sync_session_factory()
    with SessionLocal() as session:
-        settings = session.execute(
-            select(ImportSettings).where(ImportSettings.id == 1)
-        ).scalar_one()
+        settings = ImportSettings.load_sync(session)
        import_root = Path(settings.import_scan_path)

        batch = ImportBatch(
@@ -96,7 +102,9 @@ def scan_directory(self, triggered_by: str = "manual",
            task = ImportTask(
                batch_id=batch_id,
                source_path=entry_str,
-                task_type="media",
+                # Archives route to import_archive_file (larger time
+                # budget) — they run the per-member pipeline inline.
+                task_type="archive" if is_archive(entry) else "media",
                status="pending",
                size_bytes=size,
            )
@@ -115,15 +123,16 @@ def scan_directory(self, triggered_by: str = "manual",
            batch.finished_at = datetime.now(UTC)
        session.commit()

-        # Now enqueue import_media_file for each pending task.
+        # Now enqueue each pending task on the right Celery task
+        # (media vs archive) via the shared router.
+        from .import_file import enqueue_import
+
        for task in session.execute(
            select(ImportTask).where(ImportTask.batch_id == batch_id)
        ).scalars():
            task.status = "queued"
            session.add(task)
-            from .import_file import import_media_file
-
-            import_media_file.delay(task.id)
+            enqueue_import(task.id, task.task_type)
        session.commit()

        if mode == "deep":
@@ -137,16 +146,12 @@ def scan_directory(self, triggered_by: str = "manual",
 # --- FC-3d: periodic source-check tick ------------------------------------


-def _async_session_factory():
-    cfg = get_config()
-    engine = create_async_engine(cfg.database_url, future=True, pool_pre_ping=True)
-    return async_sessionmaker(engine, class_=AsyncSession, expire_on_commit=False), engine
-
-
 async def _tick_due_sources_async() -> dict:
-    factory, engine = _async_session_factory()
+    factory, engine = async_session_factory()
    try:
        async with factory() as session:
+            # Prove the scheduler is alive even on empty ticks (UI reads this).
+            await record_tick(session)
            due = await select_due_sources(session)
            if not due:
                return {
@@ -20,14 +20,32 @@ IMAGES_ROOT = Path("/images")
 THUMB_MAGIC_JPEG = b"\xff\xd8\xff"
 THUMB_MAGIC_PNG = b"\x89PNG\r\n\x1a\n"

+# Minimum file size for a thumbnail to count as valid. Anything smaller
+# is almost certainly truncated/corrupt — a legitimate 400×400 JPEG@85
+# bottoms out around 2KB even on a solid-color image; 400×400 PNG starts
+# around 1KB. 256 bytes is well below any real thumbnail and well above
+# header-only corrupt files (~8-12 bytes). Operator-flagged 2026-06-01:
+# header-only corrupt files were silently passing the magic-byte check
+# and backfill counted them as "ok" — so broken-image tiles in the UI
+# never got regenerated even after running backfill.
+MIN_THUMB_BYTES = 256
+

 def _thumb_is_valid(path: Path) -> bool:
-    """Return True iff `path` exists and starts with a JPEG or PNG magic header.
+    """Return True iff `path` exists, starts with a JPEG or PNG magic
+    header, AND is at least MIN_THUMB_BYTES on disk.

-    The on-disk thumbnail format is set by services/thumbnailer.py — JPEG for
-    opaque sources, PNG for alpha sources. Anything else (missing file, OSError,
-    truncated, wrong magic) is invalid.
+    The on-disk thumbnail format is set by services/thumbnailer.py — JPEG
+    for opaque sources, PNG for alpha sources. Anything else (missing
+    file, OSError, truncated below the size floor, wrong magic) is
+    invalid and gets re-enqueued.
    """
+    try:
+        size = path.stat().st_size
+    except OSError:
+        return False
+    if size < MIN_THUMB_BYTES:
+        return False
    try:
        with path.open("rb") as f:
            head = f.read(12)
@@ -42,6 +60,59 @@ def _thumb_is_valid(path: Path) -> bool:
    return False


+def _run_backfill_scan() -> dict:
+    """Synchronous scan logic shared by the Celery task and the API
+    endpoint. Returns {enqueued, ok, regenerated, scanned}.
+
+    Operator-flagged 2026-06-01: the original task was fire-and-forget,
+    so the admin UI couldn't show what backfill actually found —
+    operator saw \"Enqueued.\" with no counts and assumed nothing was
+    happening. Now the API runs this synchronously and returns the
+    real numbers; the periodic Celery task wraps it too."""
+    from sqlalchemy import select, update
+
+    SessionLocal = _sync_session_factory()
+    enqueued = 0
+    ok = 0
+    regenerated = 0
+    scanned = 0
+    last_id = 0
+    with SessionLocal() as session:
+        while True:
+            rows = session.execute(
+                select(ImageRecord.id, ImageRecord.thumbnail_path)
+                .where(ImageRecord.id > last_id)
+                .order_by(ImageRecord.id.asc())
+                .limit(500)
+            ).all()
+            if not rows:
+                break
+            scanned += len(rows)
+            for image_id, thumb_path in rows:
+                if thumb_path is None:
+                    generate_thumbnail.delay(image_id)
+                    enqueued += 1
+                elif _thumb_is_valid(Path(thumb_path)):
+                    ok += 1
+                else:
+                    session.execute(
+                        update(ImageRecord)
+                        .where(ImageRecord.id == image_id)
+                        .values(thumbnail_path=None)
+                    )
+                    generate_thumbnail.delay(image_id)
+                    enqueued += 1
+                    regenerated += 1
+            session.commit()
+            last_id = rows[-1][0]
+    return {
+        "scanned": scanned,
+        "enqueued": enqueued,
+        "ok": ok,
+        "regenerated": regenerated,
+    }
+
+
@celery.task(
    name="backend.app.tasks.thumbnail.generate_thumbnail",
    bind=True,
@@ -84,48 +155,15 @@ def backfill_thumbnails(self) -> dict:
    """Scan ImageRecord and enqueue generate_thumbnail for rows whose
    thumbnail is missing, gone from disk, or has wrong magic bytes.

-    Keyset paginates by id ASC, page size 500. NULLs out thumbnail_path for
-    rows that point at a missing or corrupt file before enqueueing — keeps
-    the DB self-consistent on partial runs and makes re-runs safe.
+    Keyset paginates by id ASC, page size 500. NULLs out thumbnail_path
+    for rows that point at a missing or corrupt file before enqueueing —
+    keeps the DB self-consistent on partial runs and makes re-runs safe.

-    Returns {"enqueued": N, "ok": M, "regenerated": K} where:
-      - enqueued = total generate_thumbnail.delay() calls
-      - ok       = rows whose existing thumbnail file is valid (skipped)
-      - regenerated = subset of enqueued that had a non-NULL thumbnail_path
-                      cleared (i.e. missing + corrupt)
+    Returns {scanned, enqueued, ok, regenerated} where:
+      - scanned    = total rows examined
+      - enqueued   = total generate_thumbnail.delay() calls
+      - ok         = rows whose existing thumbnail file is valid (skipped)
+      - regenerated = subset of enqueued that had a non-NULL
+                      thumbnail_path cleared (i.e. missing + corrupt)
    """
-    from sqlalchemy import select, update
-
-    SessionLocal = _sync_session_factory()
-    enqueued = 0
-    ok = 0
-    regenerated = 0
-    last_id = 0
-    with SessionLocal() as session:
-        while True:
-            rows = session.execute(
-                select(ImageRecord.id, ImageRecord.thumbnail_path)
-                .where(ImageRecord.id > last_id)
-                .order_by(ImageRecord.id.asc())
-                .limit(500)
-            ).all()
-            if not rows:
-                break
-            for image_id, thumb_path in rows:
-                if thumb_path is None:
-                    generate_thumbnail.delay(image_id)
-                    enqueued += 1
-                elif _thumb_is_valid(Path(thumb_path)):
-                    ok += 1
-                else:
-                    session.execute(
-                        update(ImageRecord)
-                        .where(ImageRecord.id == image_id)
-                        .values(thumbnail_path=None)
-                    )
-                    generate_thumbnail.delay(image_id)
-                    enqueued += 1
-                    regenerated += 1
-            session.commit()
-            last_id = rows[-1][0]
-    return {"enqueued": enqueued, "ok": ok, "regenerated": regenerated}
+    return _run_backfill_scan()
@@ -0,0 +1,33 @@
+"""Subprocess entrypoint for safe_probe.probe_archive — see safe_probe.py.
+
+probe_archive spawns this via subprocess (not multiprocessing.Process)
+because Celery's prefork worker pool runs tasks in DAEMON processes and
+Python's multiprocessing forbids daemon processes from spawning children
+("AssertionError: daemonic processes are not allowed to have children",
+operator-flagged 2026-05-30 — every archive import failed at task
+startup). subprocess has no such restriction; we still get crash-
+isolation because a probe segfault/OOM exits non-zero rather than
+killing the worker.
+
+Prints a single JSON line on stdout: {"status": "ok"|"error",
+"detail": "..."?}. Exit code 0 for clean outcomes; non-zero exit
+(signal / OOM-kill / unhandled exception) is the poison-pill signature
+the parent maps to ProbeResult(crashed=True).
+"""
+import json
+import sys
+
+from .safe_probe import _run_probe
+
+
+def main() -> int:
+    if len(sys.argv) != 2:
+        print(json.dumps({"status": "error", "detail": "usage: <path>"}))
+        return 2
+    status, detail = _run_probe(sys.argv[1])
+    print(json.dumps({"status": status, "detail": detail}))
+    return 0
+
+
+if __name__ == "__main__":
+    sys.exit(main())
@@ -0,0 +1,191 @@
+"""Subprocess-isolated media probes (Layer 3 of import resilience).
+
+A malformed video or archive can hard-crash the worker process — a
+decoder OOM, a native-lib segfault, or a decompression bomb. A hard
+crash leaves no terminal flip, so the recovery sweep re-queues the row
+and it crashes again: a poison-pill loop (the Layer-1 cap is the
+backstop, but isolating the crash is better — the file gets a clean
+terminal failure and the worker never dies).
+
+These probes run the risky read in a way that contains the blast:
+
+- Video: `ffprobe` is a separate binary, so a crash decoding the
+  container kills only ffprobe (non-zero exit), never the worker. Also
+  returns width/height, which the importer didn't previously capture
+  for videos.
+- Archive: an uncompressed-size guard (catches decompression bombs
+  before they OOM anything) plus an integrity test in a spawned child
+  (catches native-lib crashes on a malformed archive). A child segfault
+  / OOM shows up as a non-zero exit code, not a dead worker.
+
+Images are intentionally NOT probed here: Pillow raises (it doesn't
+segfault) on the realistic corrupt-image cases, the importer already
+catches that as an invalid_image skip, and a subprocess per image would
+wreck deep-scan throughput on a large library. Add an image branch only
+if a real image-induced worker crash is ever observed.
+
+Operator-requested 2026-05-28 (Layer 3).
+"""
+
+import json
+import subprocess
+import sys
+from dataclasses import dataclass
+from pathlib import Path
+
+VIDEO_PROBE_TIMEOUT_SECONDS = 60
+ARCHIVE_PROBE_TIMEOUT_SECONDS = 120
+# Refuse archives whose total UNCOMPRESSED size exceeds this — the
+# classic decompression-bomb guard (a 4 GB cap comfortably clears real
+# art-pack archives while stopping a few-KB zip that expands to TB).
+MAX_ARCHIVE_UNCOMPRESSED_BYTES = 4 * 1024 * 1024 * 1024
+
+# Repo root for the subprocess cwd so `python -m backend.app.utils.*`
+# resolves regardless of where Celery / pytest started. backend/app/utils
+# = parents[0]; backend/app = parents[1]; backend = parents[2]; repo root
+# = parents[3].
+_REPO_ROOT = Path(__file__).resolve().parents[3]
+_PROBE_RUNNER_MODULE = "backend.app.utils._archive_probe_runner"
+
+
+@dataclass(frozen=True)
+class ProbeResult:
+    ok: bool
+    # crashed=True means the probe HARD-FAILED (subprocess killed by a
+    # signal, OOM, or timeout) — the poison-pill signature. crashed=False
+    # with ok=False means a clean rejection (corrupt-but-handled,
+    # bomb-size-exceeded, integrity mismatch). Callers map crashed → a
+    # terminal 'failed', clean → a 'skipped'/'failed' of their choosing.
+    crashed: bool = False
+    reason: str | None = None
+    width: int | None = None
+    height: int | None = None
+
+
+def probe_video(path: Path, *, timeout: float = VIDEO_PROBE_TIMEOUT_SECONDS) -> ProbeResult:
+    """Validate a video container + first video stream via ffprobe."""
+    try:
+        out = subprocess.run(
+            [
+                "ffprobe", "-v", "error",
+                "-select_streams", "v:0",
+                "-show_entries", "stream=width,height",
+                "-of", "json", str(path),
+            ],
+            capture_output=True, text=True, timeout=timeout,
+        )
+    except subprocess.TimeoutExpired:
+        return ProbeResult(ok=False, crashed=True, reason="ffprobe timed out")
+    except OSError as exc:
+        # ffprobe missing / not executable — environmental, not the
+        # file's fault. Treat as a clean non-crash failure so the import
+        # path can decide (it currently proceeds without dims).
+        return ProbeResult(ok=False, crashed=False, reason=f"ffprobe unavailable: {exc}")
+    if out.returncode != 0:
+        return ProbeResult(
+            ok=False, crashed=False,
+            reason=f"ffprobe rejected the file: {out.stderr.strip()[:200]}",
+        )
+    try:
+        streams = (json.loads(out.stdout) or {}).get("streams") or []
+    except json.JSONDecodeError as exc:
+        return ProbeResult(ok=False, crashed=False, reason=f"ffprobe output parse failed: {exc}")
+    if not streams:
+        return ProbeResult(ok=False, crashed=False, reason="no decodable video stream")
+    return ProbeResult(
+        ok=True, width=streams[0].get("width"), height=streams[0].get("height"),
+    )
+
+
+def probe_archive(path: Path, *, timeout: float = ARCHIVE_PROBE_TIMEOUT_SECONDS) -> ProbeResult:
+    """Bomb-size guard + isolated integrity test for an archive.
+
+    Runs via subprocess (not multiprocessing.Process) because Celery's
+    prefork worker pool is daemon-mode and Python's multiprocessing
+    forbids daemon processes from spawning children ("AssertionError:
+    daemonic processes are not allowed to have children"). subprocess
+    has no such restriction and still gives the crash isolation: a probe
+    segfault/OOM exits non-zero rather than killing the worker.
+    """
+    try:
+        result = subprocess.run(
+            [sys.executable, "-m", _PROBE_RUNNER_MODULE, str(path)],
+            capture_output=True, text=True, timeout=timeout,
+            cwd=str(_REPO_ROOT),
+        )
+    except subprocess.TimeoutExpired:
+        return ProbeResult(ok=False, crashed=True, reason="archive probe timed out")
+    if result.returncode != 0:
+        # Negative = killed by signal (segfault); positive = unhandled
+        # exception or OOM-kill. Either way: poison-pill signature.
+        return ProbeResult(
+            ok=False, crashed=True,
+            reason=f"archive probe crashed (exit {result.returncode})",
+        )
+    last_line = result.stdout.strip().splitlines()[-1:] or [""]
+    try:
+        outcome = json.loads(last_line[0])
+    except json.JSONDecodeError as exc:
+        return ProbeResult(
+            ok=False, crashed=True,
+            reason=f"archive probe produced no parseable result: {exc}",
+        )
+    if outcome.get("status") == "ok":
+        return ProbeResult(ok=True)
+    return ProbeResult(
+        ok=False, crashed=False,
+        reason=outcome.get("detail") or "archive probe rejected",
+    )
+
+
+def _run_probe(path_str: str) -> tuple[str, str | None]:
+    """Pure-Python body of the archive probe — bomb-guard + integrity test.
+
+    Returns ('ok', None) or ('error', reason). Caught exceptions become
+    clean 'error' rejections; uncaught crashes in the subprocess become
+    non-zero exit codes (poison-pill signature) handled by probe_archive.
+
+    Exposed at the module level so the subprocess runner and tests both
+    call the same code path.
+    """
+    path = Path(path_str)
+    ext = path.suffix.lower()
+    try:
+        total, test_bad = _inspect_archive(path, ext)
+    except Exception as exc:  # noqa: BLE001 — clean rejection
+        return ("error", f"{type(exc).__name__}: {exc}")
+    if total is not None and total > MAX_ARCHIVE_UNCOMPRESSED_BYTES:
+        gib = total / (1024 ** 3)
+        return ("error", f"uncompressed size {gib:.1f} GiB exceeds the bomb-guard cap")
+    if test_bad is not None:
+        return ("error", f"integrity test failed at member {test_bad!r}")
+    return ("ok", None)
+
+
+def _inspect_archive(path: Path, ext: str):
+    """Return (total_uncompressed_bytes | None, first_bad_member | None)
+    for the archive. Format-specific; raises on a structurally-broken
+    container (caught by the child as a clean rejection)."""
+    if ext in (".zip", ".cbz"):
+        import zipfile
+
+        with zipfile.ZipFile(path) as zf:
+            total = sum(zi.file_size for zi in zf.infolist())
+            return total, zf.testzip()
+    if ext == ".rar":
+        import rarfile
+
+        with rarfile.RarFile(path) as rf:
+            total = sum(getattr(ri, "file_size", 0) for ri in rf.infolist())
+            rf.testrar()
+            return total, None
+    if ext == ".7z":
+        import py7zr
+
+        with py7zr.SevenZipFile(path, "r") as zf:
+            info = zf.archiveinfo()
+            total = getattr(info, "uncompressed", None)
+            ok = zf.test()  # True / None when all members pass
+            return total, (None if ok in (True, None) else "7z test reported corruption")
+    # Unknown extension — nothing to test; treat as clean.
+    return None, None
@@ -1,7 +1,9 @@
 """Minimal gallery-dl sidecar parsing (one-time filesystem-import aid).

-No per-platform branching: a small common key set with fallbacks; the
-full JSON is kept in raw so anything unmapped is recoverable later.
+Per-platform quirks (post_url synthesis, key-chain overrides) live in
+the platforms registry — `backend/app/services/platforms/`. This module
+is platform-agnostic: it looks up `category` in the sidecar and asks
+the registry for the right behavior.
 """

 import re
@@ -9,6 +11,12 @@ from dataclasses import dataclass
 from datetime import UTC, datetime
 from pathlib import Path

+from ..services.platforms import (
+    PLATFORMS,
+    description_keys_for,
+    external_post_id_keys_for,
+)
+

@dataclass(frozen=True)
 class SidecarData:
@@ -55,6 +63,46 @@ def _first_str(data: dict, keys: tuple[str, ...]) -> str | None:
    return None


+def _first_id(data: dict, keys: tuple[str, ...]) -> str | None:
+    """Like `_first_str` but accepts ints and rejects bool (Python's
+    bool subclasses int, so a literal `"id": true` would otherwise
+    yield external_post_id="True")."""
+    for k in keys:
+        v = data.get(k)
+        if isinstance(v, bool):
+            continue
+        if isinstance(v, (str, int)) and str(v).strip():
+            return str(v).strip()
+    return None
+
+
+# Strip HTML tags + collapse whitespace + take the first non-empty line.
+# Used to derive a display title from a body when the platform doesn't
+# expose a separate title field (subscribestar posts always write
+# `title: ""` and put the leading sentence inside `content` as HTML).
+# Truncated to 120 chars with an ellipsis if longer — long enough to be
+# meaningful in a feed, short enough to fit a row.
+_TAG_RE = re.compile(r"<[^>]+>")
+_WS_RE = re.compile(r"\s+")
+
+
+def _first_line_text(body: str, limit: int = 120) -> str | None:
+    if not body:
+        return None
+    text = _TAG_RE.sub(" ", body)
+    text = text.replace("\xa0", " ")
+    # Split on hard line breaks first; the body-stripped HTML often
+    # collapses to one logical line, in which case the first sentence
+    # split is the next-best heuristic.
+    for line in text.splitlines():
+        line = _WS_RE.sub(" ", line).strip()
+        if line:
+            if len(line) > limit:
+                return line[: limit - 1].rstrip() + "…"
+            return line
+    return None
+
+
 def _parse_date(v) -> datetime | None:
    if isinstance(v, bool):
        return None
@@ -84,14 +132,7 @@ def parse_sidecar(data: dict) -> SidecarData:
    cat = data.get("category")
    platform = cat if isinstance(cat, str) and cat.strip() else None

-    external_post_id = None
-    for k in ("id", "post_id", "index", "message_id"):
-        v = data.get(k)
-        if isinstance(v, bool):
-            continue
-        if isinstance(v, (str, int)) and str(v).strip():
-            external_post_id = str(v)
-            break
+    external_post_id = _first_id(data, external_post_id_keys_for(platform))

    pc = data.get("page_count")
    if isinstance(pc, bool):
@@ -111,12 +152,32 @@ def parse_sidecar(data: dict) -> SidecarData:
            if post_date is not None:
                break

+    description = _first_str(data, description_keys_for(platform))
+
+    # When `title` is empty (subscribestar always; sometimes elsewhere),
+    # synthesize from the description body's first non-empty text line.
+    # Patreon's explicit titles short-circuit the fallback.
+    post_title = _first_str(data, ("title",))
+    if post_title is None and description:
+        post_title = _first_line_text(description)
+
+    # post_url: ask the platform module to synthesize a permalink.
+    # When the platform registers a `derive_post_url`, it owns the
+    # field (the bare `url`/`post_url` value is a file CDN URL and
+    # must NEVER be persisted). When it doesn't register one, trust
+    # the sidecar's `url` (Patreon's case — real permalink).
+    info = PLATFORMS.get(platform) if platform else None
+    if info is not None and info.derive_post_url is not None:
+        post_url = info.derive_post_url(data)
+    else:
+        post_url = _first_str(data, ("url", "post_url"))
+
    return SidecarData(
        platform=platform,
        external_post_id=external_post_id,
-        post_url=_first_str(data, ("url", "post_url")),
-        post_title=_first_str(data, ("title",)),
-        description=_first_str(data, ("content", "description", "caption")),
+        post_url=post_url,
+        post_title=post_title,
+        description=description,
        attachment_count=attachment_count,
        post_date=post_date,
        raw=data,
@@ -0,0 +1,46 @@
+"""Parse the user-facing `kind:name` shortcut used by the add-tag input.
+
+Mirrors IR's app/utils/tag_prefix.py. Tag.name in FC is stored bare;
+the `kind:` prefix only exists as an input convention at user-facing
+places (image-modal add-tag input, future bulk-add forms). The parser
+is the single owner of the kind-string list — anything not in
+KNOWN_KINDS keeps its colon as literal text.
+"""
+
+from __future__ import annotations
+
+# Kinds the user can type as a prefix at the input boundary.
+# Exclusions:
+#   - `general` is the default for un-prefixed input (never typed as prefix)
+#   - `archive`, `post` are system-managed
+#   - `artist` was retired in FC-2d-vii-c — artists are first-class
+#     entities (Artist row + ImageRecord.artist_id), browsed via the
+#     provenance axis rather than as tags. See project_provenance_separation.
+#   - `meta`, `rating` retired as user-typeable per operator 2026-05-26 —
+#     content classification only needs character/fandom/series.
+KNOWN_KINDS: frozenset[str] = frozenset({
+    "character",
+    "fandom",
+    "series",
+})
+
+
+def parse_kind_prefix(raw: str) -> tuple[str | None, str]:
+    """Split a raw user-typed tag string into (kind, name).
+
+    Returns (kind, name) where kind is lowercase canonical and in
+    KNOWN_KINDS, or (None, raw.strip()) if no recognized prefix is
+    present. `name` is always whitespace-stripped.
+
+    Examples:
+        parse_kind_prefix("character:Saber") -> ("character", "Saber")
+        parse_kind_prefix("Character:Saber") -> ("character", "Saber")
+        parse_kind_prefix("sunset")          -> (None, "sunset")
+        parse_kind_prefix("http://example")  -> (None, "http://example")
+        parse_kind_prefix("fandom: FSN ")    -> ("fandom", "FSN")
+    """
+    if ":" in raw:
+        prefix, rest = raw.split(":", 1)
+        if prefix.lower() in KNOWN_KINDS:
+            return prefix.lower(), rest.strip()
+    return None, raw.strip()
@@ -194,9 +194,20 @@ browser.runtime.onMessage.addListener(async (msg) => {
        if (platform.authType === 'cookies') {
          const cookies = await extractCookiesForPlatform(key);
          if (cookies.length === 0) return { error: 'No cookies found — log in first.' };
+          // Verify the captured cookies are actually live BEFORE
+          // uploading. Skips upload on confirmed-stale sessions so we
+          // don't overwrite FC-side credentials with garbage. Platforms
+          // without a verify config (verify.ok === null) fall through
+          // to upload as before.
+          const v = await verifyCookiesForPlatform(key);
+          if (v.ok === false) {
+            return {
+              error: `Captured ${cookies.length} ${platform.name} cookies but they don't appear authenticated (${v.reason}). Log in again in this browser, then retry.`,
+            };
+          }
          const data = toNetscapeFormat(cookies);
          await api.uploadCredentials(key, 'cookies', data);
-          return { success: true, cookieCount: cookies.length };
+          return { success: true, cookieCount: cookies.length, verified: v.ok === true };
        }
        if (key === 'discord') {
          if (!discordToken) return { error: 'Open discord.com to capture a token first.' };
@@ -229,8 +240,13 @@ browser.runtime.onMessage.addListener(async (msg) => {
            results[key] = { skipped: true, reason: 'no cookies' };
            continue;
          }
+          const v = await verifyCookiesForPlatform(key);
+          if (v.ok === false) {
+            results[key] = { error: `verify failed: ${v.reason}` };
+            continue;
+          }
          await api.uploadCredentials(key, 'cookies', toNetscapeFormat(cookies));
-          results[key] = { success: true, cookieCount: cookies.length };
+          results[key] = { success: true, cookieCount: cookies.length, verified: v.ok === true };
        } catch (e) {
          results[key] = { error: e.message };
        }
@@ -259,6 +275,29 @@ browser.runtime.onMessage.addListener(async (msg) => {
        return { error: e.message };
      }

+    case 'PROBE_SOURCE':
+      try {
+        return await api.probeSource(msg.url);
+      } catch (e) {
+        return { error: e.message };
+      }
+
+    case 'OPEN_ARTIST_PAGE': {
+      // apiUrl is configured with the /api suffix (see
+      // options/options.html placeholder); the SPA artist route is
+      // /artist/:slug, served from the same origin. Strip /api so the
+      // browser-level URL hits the Vue router, not the JSON API.
+      const base = (api.baseUrl || '').replace(/\/+$/, '').replace(/\/api$/, '');
+      const slug = encodeURIComponent(msg.slug || '');
+      if (!base || !slug) return { error: 'apiUrl or slug missing' };
+      try {
+        await browser.tabs.create({ url: `${base}/artist/${slug}` });
+        return { success: true };
+      } catch (e) {
+        return { error: e.message };
+      }
+    }
+
    default:
      return { error: `Unknown message type: ${msg.type}` };
  }
@@ -5,11 +5,26 @@
  background: rgb(20, 23, 26); color: rgb(244, 186, 122);
  font: 500 14px/1.2 system-ui, sans-serif;
  box-shadow: 0 4px 16px rgba(0, 0, 0, 0.4); cursor: pointer;
-  transition: transform 100ms ease;
+  transition: transform 100ms ease, background 150ms ease, color 150ms ease;
 }
 .fc-add-source-btn:hover { transform: translateY(-1px); }
 .fc-add-source-btn:disabled { opacity: 0.6; cursor: wait; }

+/* state colors map to the FC palette: parchment-on-slate base,
+   accent-orange for new, sage for already-subscribed, amber-warning for
+   artist-exists-but-source-missing. All readable on the dark base. */
+.fc-add-source-btn--new {
+  background: rgb(20, 23, 26); color: rgb(244, 186, 122);
+}
+.fc-add-source-btn--artist-match {
+  background: rgb(28, 23, 16); color: rgb(255, 200, 120);
+  border: 1px solid rgb(180, 130, 60);
+}
+.fc-add-source-btn--source-match {
+  background: rgb(18, 28, 20); color: rgb(140, 220, 160);
+  border: 1px solid rgb(80, 160, 100);
+}
+
 .fc-toast {
  all: revert;
  position: fixed; bottom: 84px; right: 24px; z-index: 2147483647;
@@ -2,6 +2,10 @@
  if (window.__fc_addsource_injected) return;
  window.__fc_addsource_injected = true;

+  // Cached probe result for the current URL so click-handlers know which
+  // action to dispatch without round-tripping again.
+  let currentProbe = null;
+
  evaluate();

  const reEval = () => evaluate();
@@ -9,38 +13,116 @@
  const origPush = history.pushState;
  history.pushState = function () { origPush.apply(this, arguments); reEval(); };

-  function evaluate() {
-    const platform = getPlatformFromUrl(window.location.href);
-    const onArtist = platform && isArtistPage(window.location.href, platform);
-    let btn = document.getElementById('fc-add-source-btn');
-    if (onArtist && !btn) injectButton();
-    else if (!onArtist && btn) btn.remove();
+  async function evaluate() {
+    const url = window.location.href;
+    const platform = getPlatformFromUrl(url);
+    const onArtist = platform && isArtistPage(url, platform);
+    const btn = document.getElementById('fc-add-source-btn');
+    if (!onArtist) {
+      if (btn) btn.remove();
+      currentProbe = null;
+      return;
+    }
+    // On artist pages, ask the backend what state the URL is in BEFORE
+    // injecting the button — so the chip can render the right state on
+    // first paint instead of flashing the generic "Add" copy and
+    // updating afterwards.
+    let probe;
+    try {
+      probe = await browser.runtime.sendMessage({ type: 'PROBE_SOURCE', url });
+    } catch (e) {
+      probe = { error: e?.message || 'probe failed' };
+    }
+    currentProbe = probe;
+    if (probe?.state === 'unknown_platform') {
+      if (btn) btn.remove();
+      return;
+    }
+    renderButton(probe);
  }

-  function injectButton() {
-    const btn = document.createElement('button');
-    btn.id = 'fc-add-source-btn';
+  function renderButton(probe) {
+    let btn = document.getElementById('fc-add-source-btn');
+    if (!btn) {
+      btn = document.createElement('button');
+      btn.id = 'fc-add-source-btn';
+      btn.addEventListener('click', onClick);
+      document.body.appendChild(btn);
+    }
+    // Reset state classes so re-renders (SPA navigation) don't stack.
    btn.className = 'fc-add-source-btn';
-    btn.textContent = '+ Add to FabledCurator';
-    btn.addEventListener('click', onClick);
-    document.body.appendChild(btn);
+    btn.classList.add(`fc-add-source-btn--${stateModifier(probe)}`);
+    btn.textContent = labelFor(probe);
+    btn.disabled = false;
+  }
+
+  function stateModifier(probe) {
+    if (!probe || probe.error) return 'new';
+    return ({
+      source_match: 'source-match',
+      artist_match: 'artist-match',
+      new: 'new',
+    })[probe.state] || 'new';
+  }
+
+  function labelFor(probe) {
+    if (!probe || probe.error) return '+ Add to FabledCurator';
+    const platformName = platformDisplayName(probe.platform);
+    const artistName = probe.artist?.name;
+    switch (probe.state) {
+      case 'source_match':
+        return `✓ In FabledCurator · ${platformName}`;
+      case 'artist_match':
+        return `+ Add ${platformName} source to ${artistName || 'artist'}`;
+      case 'new':
+      default:
+        return '+ Add to FabledCurator';
+    }
+  }
+
+  function platformDisplayName(key) {
+    return PLATFORMS[key]?.name || key || '';
  }

  async function onClick() {
    const btn = document.getElementById('fc-add-source-btn');
+    if (!btn) return;
    btn.disabled = true;
    const original = btn.textContent;
+    const probe = currentProbe;
+
+    if (probe?.state === 'source_match') {
+      btn.textContent = 'Opening…';
+      try {
+        const r = await browser.runtime.sendMessage({
+          type: 'OPEN_ARTIST_PAGE',
+          slug: probe.artist?.slug,
+        });
+        if (r?.error) showToast(`Error: ${r.error}`, 'error');
+      } catch (e) {
+        showToast(`Error: ${e.message}`, 'error');
+      } finally {
+        btn.disabled = false;
+        btn.textContent = original;
+      }
+      return;
+    }
+
    btn.textContent = 'Adding…';
    try {
      const r = await browser.runtime.sendMessage({
        type: 'ADD_AS_SOURCE',
        url: window.location.href,
      });
-      if (r.error) {
+      if (r?.error) {
        showToast(`Error: ${r.error}`, 'error');
      } else {
        const verb = r.created_source ? 'Added' : 'Already a source for';
        showToast(`${verb} ${r.artist?.name || 'artist'} (${r.source?.platform || ''})`, 'success');
+        // Re-probe so the chip flips green without waiting for the next
+        // navigation.
+        evaluate();
+        return;
      }
    } catch (e) {
      showToast(`Error: ${e.message}`, 'error');
@@ -83,6 +83,12 @@ class FabledCuratorAPI {
  quickAddSource(url) {
    return this.request('POST', '/extension/quick-add-source', { url });
  }
+  probeSource(url) {
+    // Read-only existence check. Drives the content-script chip's
+    // color/copy BEFORE the operator clicks Add.
+    const qs = new URLSearchParams({ url }).toString();
+    return this.request('GET', `/extension/probe?${qs}`);
+  }

  // Connection test = the cheapest read with auth.
  testConnection() {
--- a/Show More
+++ b/Show More