Upload: surface a clear message on 413 instead of raw 'Request failed with status 413'

[a-essawy]

Problem

Uploading a file >100MB shows the raw HTTP status:

  ✗ Uploading  Request failed with status 413

The 413 is Cloudflare's 100MB Worker request-body cap (see rendobar/rendobar#212). The CLI forwards it verbatim, so the user has no idea what went wrong or what to do.

Ask

In the upload path (src/lib/upload.ts), catch the 413 and print an actionable message, e.g.:

File is too large to upload directly (100 MB limit). Pass a URL instead: rb ffmpeg -i https://...

Optional: pre-check file.size > 100MB before sending to fail fast and save the upload attempt.

Minimal scope — just better messaging.