feat(library): reindex button, live grid, archive-reappear fix, bigger carets

- Add one-click "reindex new files" button to the Library sidebar header
  (RefreshCw, calls startIndex rescan:false), spins + disables while active.
- Refresh the photos grid from the indexer WS stream (throttled during the
  scan + once on completion) so newly indexed files appear live.
- Fix archived photos flashing back into the grid when archiving others:
  drop the per-action settle-driven clearRemoved and reconcile removedIds
  against the actual cache instead (clears an id only once it's gone from
  the deduped pages). Covers archive, delete, and bulk-bar removals.
- Replace the tiny Unicode caret triangles with a 16px Lucide ChevronRight
  that rotates 90deg on expand, across folder tree rows, root, Tags, Review.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

web/src/lib/components/timeline/BulkActionBar.svelte

@@ -33,8 +33,7 @@
 		doneBulk,
 		removedBulk,
 		failBulk,
-		markRemoved,
-		clearRemoved
+		markRemoved
 	} from '$lib/stores/bulkAction.svelte';
 	import { EmptyState, InlineLoader } from '$lib/components/feedback';
 	import { Layers } from 'lucide-svelte';
@@ -156,15 +155,14 @@
 			throw e;
 		} finally {
 			busy = false;
-			const settled = Promise.all([
-				qc.invalidateQueries({ queryKey: ['photos'] }),
-				qc.invalidateQueries({ queryKey: ['marks'] }),
-				qc.invalidateQueries({ queryKey: ['review-groups'] })
-			]);
-			// Clear the optimistic-removal overlay only once the refetch has
-			// landed, so tiles never flash back in before the fresh (archived-
-			// filtered) page replaces the old one.
-			if (bulk) void settled.then(() => clearRemoved(bulk.ids));
+			void qc.invalidateQueries({ queryKey: ['photos'] });
+			void qc.invalidateQueries({ queryKey: ['marks'] });
+			void qc.invalidateQueries({ queryKey: ['review-groups'] });
+			// The optimistic-removal overlay (removedIds) is reconciled against
+			// the cache in +page.svelte — each id drops once the fresh, archived-
+			// filtered page has actually replaced it. Clearing here off this
+			// action's own settle raced other in-flight removals and flashed
+			// tiles back in.
 		}
 	}