chore: remove sync_character_fandoms maintenance task

tag.fandom_id is now authoritative. set_tag_fandom auto-applies the
fandom tag inline; add_tag already did. There's no drift to sync on
a schedule anymore.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

app/tasks/maintenance.py

@@ -1,66 +1,4 @@
-"""Maintenance-queue Celery tasks. Lightweight, user-triggered, non-ML."""
-import logging
-from celery import shared_task
-from sqlalchemy import text
-
-from app import db
-from app.models import Tag
-
-log = logging.getLogger(__name__)
-
-
-@shared_task(
-    name='app.tasks.maintenance.sync_character_fandoms',
-    soft_time_limit=120,
-    time_limit=180,
-)
-def sync_character_fandoms():
-    """For every character tag with a non-null fandom_id, attach the fandom
-    tag to every image tagged with the character but not the fandom.
-
-    Additive only — never removes fandom tags.
-
-    Returns a summary dict with counts.
-    """
-    chars = (
-        Tag.query
-        .filter_by(kind='character')
-        .filter(Tag.fandom_id.isnot(None))
-        .all()
-    )
-    total_added = 0
-    failed = 0
-    for char in chars:
-        try:
-            result = db.session.execute(
-                text("""
-                    INSERT INTO image_tags (image_id, tag_id)
-                    SELECT it.image_id, :fandom_id
-                    FROM image_tags it
-                    WHERE it.tag_id = :char_id
-                      AND NOT EXISTS (
-                          SELECT 1 FROM image_tags it2
-                          WHERE it2.image_id = it.image_id
-                            AND it2.tag_id = :fandom_id
-                      )
-                """),
-                {'char_id': char.id, 'fandom_id': char.fandom_id},
-            )
-            total_added += result.rowcount or 0
-            db.session.commit()
-        except Exception as e:
-            db.session.rollback()
-            failed += 1
-            log.warning(
-                "sync_character_fandoms: char tag %s (%s) failed: %s",
-                char.id, char.name, e,
-            )
-    log.info(
-        "sync_character_fandoms: scanned %d characters, added %d image↔fandom links, %d failed",
-        len(chars), total_added, failed,
-    )
-    return {
-        'characters_scanned': len(chars),
-        'links_added': total_added,
-        'characters_failed': failed,
-    }
+"""Maintenance-queue Celery tasks. Currently empty — the
+sync_character_fandoms task was removed on 2026-04-21 as part of the
+bare-name refactor (tag.fandom_id is now authoritative; no drift to sync).
+"""