Connect Raycast extensions to Apple Music.

This proxy wraps MusicKit authorization in a standard OAuth 2.0 authorization-code flow with PKCE, so Raycast extensions can securely request access to a user's Apple Music library.

1. 1 Start authorization

   The extension creates a PKCE challenge and opens the authorization endpoint.

2. 2 Connect Apple Music

   The user signs in with Apple and grants access through MusicKit.

3. 3 Return to Raycast

   The proxy verifies PKCE and securely returns the Apple Music user token.