fix(spotify): fallback for public playlist API 404

[deecypher]

Summary

This fixes Spotify playlist imports that fail with:

Unrecognised response code: 404 - Not Found. Body: {"error":{"status":404,"message":"Resource not found"}}

for some public playlist URLs.

What changed

• Keep existing Spotify playlist API flow first.
• If playlist fetch returns 404, fallback to parsing the public playlist page HTML:
  • Read music:song meta tags from https://open.spotify.com/playlist/:id
  • Extract track IDs
  • Resolve tracks with sp.tracks.get(...)
  • Build a spotify_playlist Convertable from resolved tracks
• Improved Spotify error-status extraction for SDK errors that only expose status in message text.
• Relaxed Spotify playlist link parsing to accept non-numeric IDs.
• Added clearer error type for inaccessible Spotify playlist API paths.

Repro / validation

• Repro URL:
  • https://open.spotify.com/playlist/37i9dQZEVXbp2RxXb8FTfF
• Before: queue error with raw Spotify SDK 404.
• After: fallback path resolves the playlist and produces a valid convertable (27 tracks in local test).

Notes

This preserves current behavior for normal playlist API access and only uses HTML fallback when Spotify playlist API returns 404 for otherwise public links.

[changeset-bot]

🦋 Changeset detected

Latest commit: 065bf5e

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 3 packages

Name	Type
deemix	Patch
deemix-webui	Patch
deemix-gui	Patch

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[deecypher]

Quick note on checks: I verified this branch locally and deemix-webui builds successfully.

pnpm --filter deemix-webui build

Given that vercel.json has "deploymentEnabled": false, the failing Vercel status appears to be an external integration/deployment context rather than a functional regression from this PR.