[8u6cherhu]

Problem

POST /api/fs/transcode/play uses the request path directly, while the regular /api/fs/* handlers first resolve it relative to the authenticated user's base_path. For users with a non-root base path, browsing can succeed but transcoding fails during storage lookup with storage not found.

Change

Resolve req.Path once with user.JoinPath and use the canonical VFS path for:

• access checking and object lookup;
• reusable-job matching;
• local-file resolution or signed /d source construction;
• the queued job path.

This keeps the transcode path consistent with the existing file APIs and does not change worker behavior, storage configuration, encoder settings, or the frontend.

Validation

• git diff --check passed.
• Reproduced the failure with a user base path and confirmed the same request succeeds when supplied with the canonical VFS path: the existing worker received the job and ran ffmpeg/NVENC.
• The patch is limited to server/handles/transcode.go.

GitHub Actions should run the repository's normal checks for the requested upstream ref.