Adds GET /photos/{id}/proxy that decodes RAW (rawpy), HEIC (pillow-heif),
and TIFF to a cached full-resolution WebP at /data/proxies/{id}.webp.
Web-safe formats (JPEG/PNG/WebP/GIF) pass through to the original to
avoid pointless transcoding. RAW failures fall back to extracting the
embedded JPEG preview. Mirrors the X-Accel-Redirect pattern from the
existing thumb endpoint.
Also fixes GET /photos/{id}/original to return the correct image/jpeg,
image/png, video/mp4, etc. content types instead of always serving
application/octet-stream, so <img> and <video> tags can render the
file inline rather than triggering a download.
Frontend: adds photos.getProxyUrl() helper in services/api.ts.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Backend generates thumbnails on-demand via Celery, so the first request
often 404s while the worker runs. Auto-retry with 1.5s/3.5s/6s backoff,
manual retry fallback, and proper timer cleanup so fast-scrolling a
virtualized timeline doesn't setState on unmounted components.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
