Spotify: Add playlist management capabilities

[jordanpartridge]

Feature Request

Enable playlist creation and management directly from the terminal.

Proposed Commands

1. View Playlists

   php 💩 spotify:playlists              # List user's playlists
   php 💩 spotify:playlists --public      # Only public playlists
   php 💩 spotify:playlist "Workout Mix"  # Show playlist tracks

2. Create/Modify Playlists

   php 💩 spotify:playlist-create "Coding Focus"
   php 💩 spotify:playlist-add "Coding Focus" --current  # Add current track
   php 💩 spotify:playlist-add "Coding Focus" "track name"
   php 💩 spotify:playlist-remove "Coding Focus" --index 5

3. Playlist Operations

   php 💩 spotify:playlist-follow "Discover Weekly"
   php 💩 spotify:playlist-shuffle "My Mix"  # Reorder randomly
   php 💩 spotify:playlist-export "My Mix" --format m3u

Additional Features

• Collaborative playlist support
• Playlist description editing
• Smart playlist creation (based on criteria)

Benefits

• Complete playlist workflow in terminal
• Batch operations on playlists
• Integration with other tools via export