Link character tags to fandom tags via fandom_id FK with auto-apply
behavior. Adding character:Saber (Fate) auto-creates fandom:Fate and
applies it to the image. Renaming a fandom cascades to all linked
characters. Includes set-fandom endpoint for retroactive association
and fandom selector dropdown in the tag editor UI.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Quick scan (default):
- Pre-load all ImportTask records for O(1) duplicate checks
- Batch task creation commits (50 at a time)
- Cache import settings (5-min TTL)
- Skip pHash comparison for speed
Deep scan (on-demand):
- Full reprocessing of all files
- pHash similarity detection
- Optional thumbnail regeneration
- Optional sidecar re-application
Archive tag merging:
- Add archive tags to existing images when duplicates found
- Works for both hash and pHash duplicate detection
Also fixes:
- Add missing source/post tag icons to gallery templates