All API credentials are now managed server-side through the Cloudflare
Workers proxy. Build workflows no longer need to inject secrets into
the binary.
Removed:
- SPOTIFY_API_CLIENT_ID/SECRET from release-linux.yml
- TIDAL_API_CLIENT_ID/SECRET from release-linux.yml
- DISCOGS_API_CLIENT_KEY/SECRET from release-linux.yml
- LAST_FM_API_KEY/SHARED_SECRET from release-linux.yml
- Complete 'Inject API secrets' step from release-flatpak.yml
This completes the API keys refactor for Flathub compliance.