Backend:
- POST /api/files/J-x/optimize/ applies a browser-processed file: replaces
every copy (renaming when the extension changes), recomputes MD5, size
and perceptual hashes, seeds guest visibility; 400 when identical,
409 when the result matches another item, owner/staff only.
Frontend (no server-side processing by design):
- optimize.worker.ts + pipelines: Mediabunny/WebCodecs for video with a
prefer-hardware hint and per-browser codec detection; MozJPEG/OxiPNG/
libwebp (jSquash) for images; gifuct-js+gifenc and UPNG for GIF/APNG.
- OptimizeModal: per-file-type options, original vs processed previews
with sizes/savings, progress bar with ETA, then Apply (overwrite).
- Optimize button on the library detail for the uploader/staff.