- Migration: add market_place_id to cart_items, page_config_id to orders
- Order model: add page_config_id FK and page_config relationship
- CartItem model: add market_place_id FK and market_place relationship
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Introduces per-page markets (Phase 2):
- MarketPlace model with soft-delete and unique slug index
- NavTop gains market_id FK to scope nav hierarchy per market
- Migration with backfill creates default 'suma-market' for existing market page
- market_url_for() cross-app URL helper
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
PostgreSQL json type doesn't support equality operators needed by
DISTINCT. Use EXISTS subquery instead and cast to jsonb.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>