Add discovery modes, personalization controls, taste profile page, updated pricing

- Discovery modes: Sonic Twin, Era Bridge, Deep Cuts, Rising Artists
- Discovery dial (Safe to Adventurous slider)
- Block genres/moods exclusion
- Thumbs down/dislike on recommendations
- My Taste page with Genre DNA breakdown, audio feature meters, listening personality
- Updated pricing: Free (5/week), Premium ($6.99/mo), Family ($12.99/mo coming soon)
- Weekly rate limiting instead of daily
- Alembic migration for new fields

backend/app/core/config.py

@@ -35,7 +35,7 @@ class Settings(BaseSettings):
     FRONTEND_URL: str = "http://localhost:5173"
 
     # Rate limits (free tier)
-    FREE_DAILY_RECOMMENDATIONS: int = 10
+    FREE_WEEKLY_RECOMMENDATIONS: int = 5
     FREE_MAX_PLAYLISTS: int = 1
 
     model_config = {"env_file": ".env", "extra": "ignore"}