Both apps kept favourites in memory only, and the API had no route, so
the 874 favourites imported from legacy major_favorites never showed.
- GET customer/me/favorites, POST customer/me/favorites/toggle
- apps load them on sign-in, clear on sign-out, toggle optimistically
and roll back on failure
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>