feat(gallery): pinned filter bar (Phase 1)

Gallery now has in-view filtering, styled like the app's sticky v-tabs
chrome (pinned at top:64px under TopNav).

- GalleryFilterBar: combined tag+artist autocomplete (searches
  /api/tags + /api/artists), closable filter chips (multi-tag AND),
  media toggle (All/Images/Videos), Newest/Oldest sort, Clear. Writes all
  state to the URL via router.push.
- gallery store: filter is now { tag_ids, artist_id, media_type, sort,
  post_id }; applyFilterFromQuery makes the URL the single source of truth
  (deep-linkable, back-button works); chip labels resolved by id or
  pre-noted on pick. Replaces the standalone tag chip + setTag/PostFilter.
- GalleryView: renders the bar (hidden in post-detail), syncs route.query
  → store on mount + every query change.

Also untracks the transient .claude/scheduled_tasks.lock committed in
3f30327 and gitignores it.

Tests: store parses query → composable scroll params, post_id exclusivity,
newest-sort omitted, label pre-seed, single initial fetch.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

.gitignore

@@ -61,6 +61,9 @@ Thumbs.db
 
 # Claude Code per-user local overrides (shared .claude/settings.json is OK to commit)
 .claude/settings.local.json
+# Transient scheduler lock/state (committed by accident in 3f30327)
+.claude/scheduled_tasks.lock
+.claude/scheduled_tasks*.json
 
 # Alembic / DB scratch
 alembic/versions/__pycache__/