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/models/recommendation.py

@@ -29,6 +29,7 @@ class Recommendation(Base):
 
     # User interaction
     saved: Mapped[bool] = mapped_column(Boolean, default=False)
+    disliked: Mapped[bool] = mapped_column(Boolean, default=False, server_default="false")
     created_at: Mapped[datetime] = mapped_column(
         DateTime(timezone=True), default=lambda: datetime.now(timezone.utc)
     )