refactor(ml): retire the Camie tagger + allowlist bulk-apply (#1189)

Heads + CCIP are the tag source and head auto-apply is the earned propagation.
The Camie tagger ran only to feed the allowlist bulk-apply (its ImagePrediction
rows had no other consumer), and the allowlist was a SECOND, un-earned auto-apply
path firing in parallel with heads on every accept — exactly the un-earned spray
the v2 pivot replaced. Retire both.

Behavior change: accepting a suggestion now applies the tag to THAT image only
(source='ml_accepted', a head-training positive) — it no longer allowlists +
fans the tag across the library via Camie. Propagation is heads' earned
auto-apply. (Loses instant cold-start propagation for booru-vocab tags; that was
un-earned and bypassed the precision gate.)

- tag_and_embed is now EMBED-ONLY (no Camie load/infer, no ImagePrediction
  writes); backfill enqueues it for images with no embedding.
- Removed: services/ml/tagger.py, apply_allowlist_tags + helpers + daily beat +
  every enqueue caller (accept/alias/merge/per-image), api/allowlist.py +
  blueprint, ImagePrediction + TagAllowlist models/tables (migration 0067),
  AllowlistTable.vue + allowlist store, the accept coverage-projection payload.
- AllowlistService gutted to accept/dismiss/undismiss/reject (the rejection store
  the rail still needs); accept returns nothing, API returns {accepted, tag_id}.
- tag merge no longer repoints/triggers the allowlist; _keep_as_alias now keys on
  ML-applied image_tag sources (incl. head_auto) instead of the allowlist.
- UI: MLBackfillCard relabelled to embedding-only; accept toast simplified;
  MaintenancePanel drops the allowlist tile.

Left for a follow-up hygiene pass (now-inert, harmless): the dead settings
columns (tagger_store_floor, tagger_model_version, suggestion_threshold_*,
video_min_tag_frames), image_record.tagger_model_version, MLThresholdSliders
trim, and the Camie model download in download_models.py.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Ttrj5P7upUTueSfoJcxEqa

tests/test_api_suggestions.py

@@ -15,9 +15,7 @@ def eager():
     celery.conf.task_always_eager = False
 
 
-async def _img(db, preds, sha="s" * 64):
-    from tests._prediction_helpers import seed_predictions
-
+async def _img(db, sha="s" * 64):
     img = ImageRecord(
         path=f"/images/{sha}.jpg", sha256=sha, size_bytes=1,
         mime="image/jpeg", width=1, height=1,
@@ -25,8 +23,6 @@ async def _img(db, preds, sha="s" * 64):
     )
     db.add(img)
     await db.commit()
-    await seed_predictions(db, img.id, preds)
-    await db.commit()
     return img
 
 
@@ -60,7 +56,7 @@ async def test_get_suggestions(client, db):
 
 @pytest.mark.asyncio
 async def test_accept_requires_tag_id(client, db):
-    img = await _img(db, {})
+    img = await _img(db)
     resp = await client.post(
         f"/api/images/{img.id}/suggestions/accept", json={}
     )
@@ -68,43 +64,31 @@ async def test_accept_requires_tag_id(client, db):
 
 
 @pytest.mark.asyncio
-async def test_accept_then_applied(client, db):
-    img = await _img(db, {})
+async def test_accept_applies_tag_to_image(client, db):
+    # Camie/allowlist retired (#1189): accept applies the tag to THIS image
+    # (source='ml_accepted', a head-training positive) — no bulk allowlist
+    # fan-out anymore.
+    from backend.app.models.tag import image_tag
+
+    img = await _img(db)
     tag = await TagService(db).find_or_create("AcceptMe", TagKind.character)
     await db.commit()
     resp = await client.post(
         f"/api/images/{img.id}/suggestions/accept", json={"tag_id": tag.id}
     )
     assert resp.status_code == 200
-    body = await resp.get_json()
-    # #7b: a fresh accept newly-allowlists → projection payload for the toast.
-    assert body["allowlisted"] is True
-    assert body["tag_id"] == tag.id
-    assert body["tag_name"] == "AcceptMe"
-    assert "projected_count" in body
-
-
-@pytest.mark.asyncio
-async def test_accept_already_allowlisted_reports_not_new(client, db):
-    img1 = await _img(db, {}, sha="c" * 64)
-    img2 = await _img(db, {}, sha="d" * 64)
-    tag = await TagService(db).find_or_create("Twice", TagKind.character)
-    await db.commit()
-    first = await client.post(
-        f"/api/images/{img1.id}/suggestions/accept", json={"tag_id": tag.id}
-    )
-    assert (await first.get_json())["allowlisted"] is True
-    second = await client.post(
-        f"/api/images/{img2.id}/suggestions/accept", json={"tag_id": tag.id}
-    )
-    body = await second.get_json()
-    assert body["allowlisted"] is False   # already on the allowlist
-    assert "projected_count" not in body
+    assert (await resp.get_json())["accepted"] is True
+    src = (await db.execute(
+        select(image_tag.c.source)
+        .where(image_tag.c.image_record_id == img.id)
+        .where(image_tag.c.tag_id == tag.id)
+    )).scalar_one()
+    assert src == "ml_accepted"
 
 
 @pytest.mark.asyncio
 async def test_dismiss(client, db):
-    img = await _img(db, {})
+    img = await _img(db)
     tag = await TagService(db).find_or_create("DismissMe", TagKind.general)
     await db.commit()
     resp = await client.post(
@@ -115,7 +99,7 @@ async def test_dismiss(client, db):
 
 @pytest.mark.asyncio
 async def test_undismiss_reverses_rejection(client, db):
-    img = await _img(db, {})
+    img = await _img(db)
     tag = await TagService(db).find_or_create("UndismissMe", TagKind.general)
     await db.commit()
     await client.post(
@@ -134,7 +118,7 @@ async def test_undismiss_reverses_rejection(client, db):
 
 @pytest.mark.asyncio
 async def test_alias_requires_fields(client, db):
-    img = await _img(db, {})
+    img = await _img(db)
     resp = await client.post(
         f"/api/images/{img.id}/suggestions/alias", json={"alias_string": "x"}
     )