Merge pull request 'v26.05.26.5 — extension CORS unblock + UI gap closes + CI workflow cleanup' (#27) from dev into main

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

.forgejo/workflows/build.yml

@@ -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)
@@ -158,8 +168,12 @@ 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.
+        if: github.ref == 'refs/heads/main' || startsWith(github.ref, 'refs/tags/')
         env:
           TOKEN: ${{ secrets.RELEASE_TOKEN }}
         run: |
@@ -200,7 +214,20 @@ jobs:
       - name: Determine tag
         id: tag
         run: |
-          if [ "${GITHUB_REF##*/}" = "main" ]; then
+          # Three trigger shapes:
+          #   refs/tags/v…   → tag-push: publish ONLY the immutable version
+          #                    tag (e.g. :v26.05.26.5). Don't touch :latest;
+          #                    that already got published by the main-push
+          #                    build for the merge commit.
+          #   refs/heads/main → push to main (incl. PR merge commits):
+          #                    publish :main + :latest (floating).
+          #   anything else  → safety net; shouldn't fire given the `on:`
+          #                    config above (dev was dropped). Tag :dev to
+          #                    surface the unexpected run in the registry.
+          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" >> "$GITHUB_OUTPUT"
           else
             echo "tags=git.fabledsword.com/bvandeusen/fabledcurator:dev" >> "$GITHUB_OUTPUT"
@@ -231,7 +258,13 @@ jobs:
       - name: Determine tag
         id: tag
         run: |
-          if [ "${GITHUB_REF##*/}" = "main" ]; then
+          # Mirrors build-web's three-shape logic (tag-push / main-push /
+          # safety-net dev). The -ml image follows the same release cadence
+          # as the web image.
+          if [ "${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 [ "${GITHUB_REF##*/}" = "main" ]; then
             echo "tags=git.fabledsword.com/bvandeusen/fabledcurator-ml:main,git.fabledsword.com/bvandeusen/fabledcurator-ml:latest" >> "$GITHUB_OUTPUT"
           else
             echo "tags=git.fabledsword.com/bvandeusen/fabledcurator-ml:dev" >> "$GITHUB_OUTPUT"

.forgejo/workflows/ci.yml

@@ -8,8 +8,10 @@ name: CI
 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:
   backend-lint-and-test:
@@ -24,13 +26,17 @@ jobs:
     steps:
       - uses: actions/checkout@v4
 
-      - name: Cache pip wheels
-        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/
@@ -124,13 +130,6 @@ jobs:
           --health-retries 10
     steps:
       - uses: actions/checkout@v4
-      - name: Cache pip wheels
-        uses: actions/cache@v4
-        with:
-          path: ~/.cache/pip
-          key: pip-${{ runner.os }}-py314-${{ hashFiles('requirements.txt') }}
-          restore-keys: |
-            pip-${{ runner.os }}-py314-
       - name: API integration shard (resolve service IPs, migrate, test)
         run: |
           set -eux
@@ -189,13 +188,6 @@ jobs:
           --health-retries 10
     steps:
       - uses: actions/checkout@v4
-      - name: Cache pip wheels
-        uses: actions/cache@v4
-        with:
-          path: ~/.cache/pip
-          key: pip-${{ runner.os }}-py314-${{ hashFiles('requirements.txt') }}
-          restore-keys: |
-            pip-${{ runner.os }}-py314-
       - name: Importer integration shard (resolve service IPs, migrate, test)
         run: |
           set -eux
@@ -254,13 +246,6 @@ jobs:
           --health-retries 10
     steps:
       - uses: actions/checkout@v4
-      - name: Cache pip wheels
-        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

alembic/versions/0022_source_per_artist_platform.py

@@ -16,12 +16,21 @@ filesystem importer was misusing Source as a per-post key.
 Migration steps per (artist_id, platform) group with >1 Source:
   1. Pick canonical — prefer a URL NOT matching '/posts/<id>$' (real
      campaign URL like /cw/Atole); else min(id).
-  2. Reparent Posts and ImageProvenance off the other Sources onto canonical.
-  3. Merge any Posts that collide on (canonical_source_id, external_post_id)
-     by repointing ImageProvenance + ImageRecord.primary_post_id to the
-     earliest Post, dedupe ImageProvenance, delete the loser Posts.
-  4. Delete the orphan Source rows.
-  5. If the canonical Source's URL still looks like a per-post URL (no
+  2. PRE-merge any Posts under non-canonical sources whose
+     external_post_id ALREADY exists under the canonical source. (Same
+     gallery-dl post imported via two different sidecar paths can plant
+     two Post rows with identical external_post_id under different
+     Sources for the same artist.) Repoint ImageProvenance +
+     ImageRecord.primary_post_id to the canonical-side Post, dedupe
+     ImageProvenance against alembic 0021's uq, then delete the
+     non-canonical-side Post. This MUST happen before step 3 — Postgres
+     fires uq_post_source_external_id row-by-row during the bulk UPDATE
+     and the merge-after-reparent ordering 500s on first collision
+     (operator-hit during v26.05.26.1 deploy, 2026-05-26).
+  3. Reparent remaining Posts onto canonical (no collisions possible now).
+  4. Reparent ImageProvenance.source_id off the non-canonical sources.
+  5. Delete the orphan Source rows.
+  6. If the canonical Source's URL still looks like a per-post URL (no
      campaign URL existed among candidates), rewrite it to
      'sidecar:<platform>:<artist_slug>' so the artist detail page shows
      something readable.
@@ -74,7 +83,84 @@ def upgrade() -> None:
         if not other_ids:
             continue
 
-        # Reparent Posts off the other Sources.
+        # 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 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()
+        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
+        # (canonical, external_post_id) are possible.
         conn.execute(
             text("""
                 UPDATE post SET source_id = :canonical
@@ -82,7 +168,9 @@ def upgrade() -> None:
             """),
             {"canonical": canonical_id, "others": other_ids},
         )
-        # Reparent ImageProvenance.source_id similarly (denormalized FK).
+
+        # STEP 4: Reparent ImageProvenance.source_id (denormalized FK).
+        # No UNIQUE on source_id; safe bulk update.
         conn.execute(
             text("""
                 UPDATE image_provenance SET source_id = :canonical
@@ -91,53 +179,7 @@ def upgrade() -> None:
             {"canonical": canonical_id, "others": other_ids},
         )
 
-        # Merge any Posts colliding on (canonical, external_post_id) after
-        # reparent. In practice within a single (artist, platform) group
-        # these should be rare — each gallery-dl post has a unique id — but
-        # safe to handle.
-        post_collisions = conn.execute(
-            text("""
-                SELECT external_post_id, ARRAY_AGG(id ORDER BY id) AS ids
-                FROM post
-                WHERE source_id = :canonical
-                GROUP BY external_post_id
-                HAVING COUNT(*) > 1
-            """),
-            {"canonical": canonical_id},
-        ).fetchall()
-        for _epid, post_ids in post_collisions:
-            keep = post_ids[0]
-            drops = post_ids[1:]
-            conn.execute(
-                text("""
-                    UPDATE image_provenance SET post_id = :keep
-                    WHERE post_id = ANY(:drops)
-                """),
-                {"keep": keep, "drops": drops},
-            )
-            conn.execute(
-                text("""
-                    UPDATE image_record SET primary_post_id = :keep
-                    WHERE primary_post_id = ANY(:drops)
-                """),
-                {"keep": keep, "drops": drops},
-            )
-            # Repointed provenance rows may now collide on
-            # uq_image_provenance_image_post (alembic 0021). Same dedupe
-            # pattern: 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 = ANY(:drops)"),
-                {"drops": drops},
-            )
-
-        # Drop the orphan Sources.
+        # STEP 5: Drop the orphan Sources.
         conn.execute(
             text("DELETE FROM source WHERE id = ANY(:others)"),
             {"others": other_ids},

backend/app/__init__.py

@@ -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")
 
 
@@ -35,6 +45,33 @@ def create_app() -> Quart:
     # 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

frontend/src/components/artist/ArtistHeader.vue

@@ -25,6 +25,11 @@
       </v-tab>
       <v-tab value="management">Management</v-tab>
     </v-tabs>
+
+    <!-- Right-side spacer: balances the left cell's flex weight so the
+         centered tabs stay geometrically centered regardless of the
+         artist-name length. Mirrors TopNav's 1fr | auto | 1fr layout. -->
+    <div class="fc-artist-header__right" />
   </header>
 </template>
 
@@ -54,11 +59,13 @@ const stats = computed(() => {
 </script>
 
 <style scoped>
-/* Matches TopNav.vue's frosted recipe exactly — top:64px parks it under
-   the 64px-tall TopNav with no visible seam. */
+/* Matches TopNav.vue's frosted recipe exactly. top:48px parks it flush
+   against TopNav's bottom edge (TopNav is 0.75rem padding + ~24px content
+   = ~48px tall; operator-flagged 2026-05-26 that top:64px left a visible
+   gap). The two bars now read as one continuous frosted strip. */
 .fc-artist-header {
   position: sticky;
-  top: 64px;
+  top: 48px;
   z-index: 4;
   display: flex;
   align-items: center;
@@ -107,6 +114,11 @@ const stats = computed(() => {
   flex: 0 0 auto;
 }
 
+.fc-artist-header__right {
+  flex: 1 1 0;
+  min-width: 0;
+}
+
 .fc-artist-header__tab-count {
   margin-left: 4px;
   font-size: 12px;

frontend/src/views/ArtistView.vue

@@ -3,11 +3,11 @@
     <v-progress-circular indeterminate color="accent" size="36" />
   </div>
 
-  <v-container v-else-if="store.notFound" class="py-6">
+  <v-container v-else-if="store.notFound" class="pt-2 pb-6">
     <v-alert type="warning" variant="tonal">Artist not found.</v-alert>
   </v-container>
 
-  <v-container v-else-if="store.error && !store.overview" class="py-6">
+  <v-container v-else-if="store.error && !store.overview" class="pt-2 pb-6">
     <v-alert type="error" variant="tonal" closable>{{ store.error }}</v-alert>
   </v-container>
 
@@ -19,7 +19,7 @@
       :post-count="store.postCount"
       :last-added="store.lastAdded"
     />
-    <v-container fluid class="py-4">
+    <v-container fluid class="pt-2 pb-4">
       <v-window v-model="tab">
         <v-window-item value="posts">
           <ArtistPostsTab

frontend/src/views/ArtistsView.vue

@@ -1,5 +1,5 @@
 <template>
-  <v-container fluid class="py-6">
+  <v-container fluid class="pt-2 pb-6">
 
     <div class="fc-artists__controls">
       <v-text-field

frontend/src/views/CredentialsView.vue

@@ -1,5 +1,5 @@
 <template>
-  <v-container fluid class="py-6">
+  <v-container fluid class="pt-2 pb-6">
     <ExtensionKeyBar />
 
     <v-alert v-if="credentialsStore.error" type="error" variant="tonal" closable class="mb-4">

frontend/src/views/DownloadsView.vue

@@ -1,5 +1,5 @@
 <template>
-  <v-container fluid class="py-6">
+  <v-container fluid class="pt-2 pb-6">
     <FilterPills v-model="pill" />
 
     <v-alert v-if="store.error" type="error" variant="tonal" closable class="my-4">

frontend/src/views/GalleryView.vue

@@ -1,5 +1,5 @@
 <template>
-  <v-container fluid class="py-6">
+  <v-container fluid class="pt-2 pb-6">
     <Teleport to="#fc-nav-actions">
       <v-btn
         :color="sel.isSelectMode ? 'accent' : undefined"

frontend/src/views/PlaceholderView.vue

@@ -1,5 +1,5 @@
 <template>
-  <v-container class="py-8">
+  <v-container class="pt-3 pb-8">
     <h1 class="fc-h1 mb-4">{{ title }}</h1>
     <v-alert type="info" variant="tonal" icon="mdi-toolbox">
       This surface is a placeholder. It will be implemented in

frontend/src/views/PostsView.vue

@@ -1,5 +1,5 @@
 <template>
-  <v-container class="py-6" max-width="900">
+  <v-container class="pt-2 pb-6" max-width="900">
     <PostsFilterBar
       :artist-id="artistFilter"
       :platform="platformFilter"

frontend/src/views/SeriesManageView.vue

@@ -1,5 +1,5 @@
 <template>
-  <v-container fluid class="py-6">
+  <v-container fluid class="pt-2 pb-6">
     <div class="fc-series__head">
       <span class="fc-series__name">{{ store.series?.name || 'Series' }}</span>
       <span class="fc-series__count">{{ store.pages.length }} page(s)</span>

frontend/src/views/SettingsView.vue

@@ -1,5 +1,5 @@
 <template>
-  <v-container fluid class="py-6">
+  <v-container fluid class="pt-2 pb-6">
     <!-- Sticky tabs: operator-flagged 2026-05-25 — long Import / Maintenance
          panels pushed the tab strip out of the viewport, forcing a scroll-
          to-top just to change tab. AppShell's TopNav is 64px sticky, so the

frontend/src/views/ShowcaseView.vue

@@ -1,5 +1,5 @@
 <template>
-  <v-container fluid class="py-6">
+  <v-container fluid class="pt-2 pb-6">
     <Teleport to="#fc-nav-actions">
       <v-btn
         prepend-icon="mdi-shuffle-variant" variant="tonal" color="accent"

frontend/src/views/SubscriptionsView.vue

@@ -1,5 +1,5 @@
 <template>
-  <v-container fluid class="py-6">
+  <v-container fluid class="pt-2 pb-6">
     <div class="fc-subs__bar">
       <v-btn color="accent" prepend-icon="mdi-plus" @click="openAddSource(null)">
         Add subscription

frontend/src/views/TagsView.vue

@@ -1,5 +1,5 @@
 <template>
-  <v-container fluid class="py-6">
+  <v-container fluid class="pt-2 pb-6">
 
     <div class="fc-tags__controls">
       <v-text-field

tests/test_extension_cors.py

@@ -0,0 +1,86 @@
+"""CORS preflight + response headers for moz-extension:// + chrome-extension://.
+
+Operator-flagged 2026-05-26: extension's first 'Test connection' tap
+returned `NetworkError` because /api/credentials had no OPTIONS handler
+and no Access-Control-Allow-Origin response header. Browser preflight
+failed → fetch blocked.
+
+These tests pin the contract: any request from a moz-extension:// or
+chrome-extension:// origin gets the right ACL headers. Plain browser
+requests (no Origin header, or a regular https:// Origin) get nothing
+— we don't want to open CORS up generally.
+"""
+
+import pytest
+
+from backend.app import create_app
+
+pytestmark = pytest.mark.integration
+
+
+@pytest.fixture
+async def client():
+    app = create_app()
+    async with app.test_client() as c:
+        yield c
+
+
+@pytest.mark.asyncio
+async def test_extension_preflight_returns_204_with_acl_headers(client):
+    resp = await client.options(
+        "/api/credentials",
+        headers={
+            "Origin": "moz-extension://abcd1234-uuid-fake",
+            "Access-Control-Request-Method": "GET",
+            "Access-Control-Request-Headers": "X-Extension-Key",
+        },
+    )
+    assert resp.status_code == 204
+    assert resp.headers["Access-Control-Allow-Origin"] == "moz-extension://abcd1234-uuid-fake"
+    assert "OPTIONS" in resp.headers["Access-Control-Allow-Methods"]
+    assert "X-Extension-Key" in resp.headers["Access-Control-Allow-Headers"]
+
+
+@pytest.mark.asyncio
+async def test_extension_get_carries_acl_headers(client):
+    # The actual response (post-preflight) also needs ACL headers — the
+    # browser checks them again before exposing the response body.
+    resp = await client.get(
+        "/api/credentials",
+        headers={"Origin": "moz-extension://abcd1234-uuid-fake"},
+    )
+    # 200 with empty list (no creds seeded) — what matters here is the
+    # CORS header is present.
+    assert resp.headers["Access-Control-Allow-Origin"] == "moz-extension://abcd1234-uuid-fake"
+
+
+@pytest.mark.asyncio
+async def test_chrome_extension_origin_also_allowed(client):
+    resp = await client.options(
+        "/api/credentials",
+        headers={
+            "Origin": "chrome-extension://abcd1234-uuid-fake",
+            "Access-Control-Request-Method": "POST",
+        },
+    )
+    assert resp.status_code == 204
+    assert resp.headers["Access-Control-Allow-Origin"] == "chrome-extension://abcd1234-uuid-fake"
+
+
+@pytest.mark.asyncio
+async def test_normal_browser_request_gets_no_cors_headers(client):
+    # A regular browser tab (https://example.com / file:// / no Origin
+    # at all) should NOT get any Access-Control-Allow-* — the extension
+    # whitelist is intentionally narrow.
+    resp = await client.get(
+        "/api/credentials",
+        headers={"Origin": "https://evil.example.com"},
+    )
+    assert "Access-Control-Allow-Origin" not in resp.headers
+
+
+@pytest.mark.asyncio
+async def test_no_origin_header_unaffected(client):
+    # Same-origin requests (no Origin header) — unaffected.
+    resp = await client.get("/api/credentials")
+    assert "Access-Control-Allow-Origin" not in resp.headers