feat: Enhance Spotify integration with app-specific tokens
- Updated Spotify token retrieval to include app-specific client IDs and secrets.
- Modified database queries to join with `spotify_apps` for fetching app-related information.
- Refactored token refresh logic to utilize app-specific credentials.
- Adjusted functions across the codebase to accommodate new parameters for client ID and secret.
- Improved error handling and logging for Spotify-related operations.
- Removed deprecated environment variable checks for client credentials.