feat: 0.1.1 — timeline scrubber, gallery virtualisation, folder reorder, QoL polish

Timeline:
- Add a right-edge scrubber (year labels + month dots) that jumps to any
  period; runs in the same direction as the scrolled content
- Load the full filtered set in Timeline view so the scrubber spans the whole
  library instead of just the first page

Gallery & UI:
- Virtualise the gallery grid
- Folder reordering in the sidebar (drag + persisted sort_order) and a themed
  dropdown component
- Subtle Light theme contrast fixes for toggles, secondary buttons and the
  update toast

Embedding workers now defer video jobs without a thumbnail at claim time and
requeue any previously-failed deferred jobs on startup, so videos no longer
churn through failed embeddings.

QoL polish across BackgroundTasks, DuplicateFinder, Lightbox and VideoPlayer.

src/components/VideoPlayer.tsx

@@ -282,7 +282,7 @@ export function VideoPlayer({ src }: { src: string }) {
   return (
     <div
       ref={containerRef}
-      className={`relative flex h-full w-full items-center justify-center bg-black ${controlsVisible ? "" : "cursor-none"}`}
+      className={`media-dark-surface relative flex h-full w-full items-center justify-center bg-black ${controlsVisible ? "" : "cursor-none"}`}
       onPointerMove={showControls}
       onClick={(event) => event.stopPropagation()}
     >