refactor(ml): drop dead tagger/suggestion settings + columns (#1199)

Hygiene follow-up to the Camie retirement (#1189) — these were left inert to
bound that change; nothing reads them now. Migration 0068 drops:
- ml_settings: tagger_store_floor, tagger_model_version, suggestion_threshold_
  character/general (already dead pre-retirement — scoring uses per-head
  thresholds), video_min_tag_frames (only the deleted video-prediction
  aggregator used it).
- image_record: tagger_model_version (no writer), centroid_scores (dead JSON
  cache, no reader).

Also: ml_admin _EDITABLE/GET/_validate pruned (dropped the store-floor invariant
+ video_min_tag_frames check); MLThresholdSliders trimmed to a video-embedding
card (interval + max frames only); importer no longer resets the dropped cols;
download_models drops the Camie fetch; stale CASCADE comments in cleanup_service
no longer name the removed tables. Tests updated.

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

backend/app/services/cleanup_service.py

@@ -395,9 +395,8 @@ def delete_images(
 def delete_tag(session: Session, *, tag_id: int) -> dict:
     """Simple DELETE FROM tag WHERE id=?.
 
-    Postgres cascades the rest (image_tag, tag_alias, tag_allowlist,
-    tag_reference_embedding, tag_suggestion_rejection, series_page).
-    Returns counts BEFORE delete so the caller can surface them.
+    Postgres cascades the rest (image_tag, tag_alias, tag_suggestion_rejection,
+    series_page). Returns counts BEFORE delete so the caller can surface them.
     Raises LookupError if tag_id not found.
     """
     tag = session.get(Tag, tag_id)
@@ -742,8 +741,7 @@ def purge_legacy_tags(session: Session, *, dry_run: bool = False) -> dict:
     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
+    CASCADE on image_tag / tag_alias / tag_suggestion_rejection / series_page
     clears the related rows on the parent DELETE.
 
     Returns:
@@ -785,23 +783,21 @@ def purge_legacy_tags(session: Session, *, dry_run: bool = False) -> dict:
     return result
 
 
-# The Camie-suggestable CONTENT vocabulary. "Reset content tagging" wipes
-# these so the operator can re-tag from scratch via auto-suggest. fandom +
-# series (and series_page ordering) are deliberately NOT here — they're kept.
+# The CONTENT vocabulary. "Reset content tagging" wipes these so the operator
+# can re-tag from scratch. fandom + series (and series_page ordering) are
+# deliberately NOT here — they're kept.
 RESETTABLE_TAG_KINDS = ("general", "character")
 
 
 def reset_content_tagging(session: Session, *, dry_run: bool = False) -> dict:
     """Count (dry_run) or DELETE every general + character tag so the operator
-    can re-tag from scratch via the Camie auto-suggest.
+    can re-tag from scratch (heads/CCIP repopulate suggestions).
 
-    PRESERVED: fandom + series tags and their series_page ordering, plus every
-    image's image_prediction rows (untouched) so suggestions
-    repopulate immediately. CASCADE on image_tag / tag_alias / tag_allowlist /
-    tag_reference_embedding / tag_suggestion_rejection clears each deleted
-    tag's applications + metadata. Tag.fandom_id is SET NULL, so deleting
-    character tags never touches the fandom rows. Irreversible except via DB
-    backup restore.
+    PRESERVED: fandom + series tags and their series_page ordering. CASCADE on
+    image_tag / tag_alias / tag_suggestion_rejection clears each deleted tag's
+    applications + metadata. Tag.fandom_id is SET NULL, so deleting character
+    tags never touches the fandom rows. Irreversible except via DB backup
+    restore.
 
     Returns:
       {"by_kind": {"general": N, "character": M},

backend/app/services/importer.py

@@ -1475,10 +1475,8 @@ class Importer:
         existing.duration_seconds = duration  # #871: keep the kept copy's duration
         existing.thumbnail_path = None
         existing.integrity_status = "unknown"
-        existing.tagger_model_version = None
         existing.siglip_embedding = None
         existing.siglip_model_version = None
-        existing.centroid_scores = None
         # created_at intentionally preserved; updated_at auto-bumps.
         self.session.flush()
         self.session.commit()