Add on-demand H.264/AAC web playback (RQ, ffmpeg) with API routes and
Next.js proxies; extend admin UI with WebPlaybackVideo and shared hooks.
Store transcode cache beside pending-photos (WEB_VIDEO_CACHE_DIR / UPLOAD_DIR)
and ignore data/web_videos. Centralize FastAPI URL helpers, optional Vite
and Next base paths for subfolder deploy, and fix modal reopen by using
router.replace when closing the home photo viewer. Include migration,
install scripts, deployment doc updates, and CI admin build env tweak.
Made-with: Cursor
