- Add slug fields to Song, Venue, Show, Tour, Performance models
- Update routers to support lookup by slug or ID
- Create slugify.py utility for generating URL-safe slugs
- Add migration script to generate slugs for existing data
- Performance slugs use songslug-YYYY-MM-DD format
- Fix ratings API to support venue_id and tour_id
- Add migration for new rating columns
- Venues list: search, state filter, sort by name/shows
- Venues detail: show list with dates, venue stats, error handling
- Remove broken EntityRating/SocialWrapper from venue pages