feat(node-player): use Service Worker for auth, enable streaming playback

Add a Service Worker that intercepts /api/* requests and injects the
Bearer token. This allows <audio> and <img> elements to use direct
URLs instead of downloading entire files as blobs first.

- Audio now streams progressively (no full download before playback)
- Cover art loads via regular <img src> (SW adds auth header)
- Remove blob-based preloadStream, fetchCoverBlob, useCoverUrl hook
- Register SW in main.tsx, token synced via postMessage

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

.gitignore

@@ -2,3 +2,4 @@
 /docker/inbox
 /docker/storage
 .env
+.DS_Store