Shopping links previously hardcoded to US storefronts. Users in other regions
got broken Amazon Fresh and Instacart links. Now locale is stored as a user
setting and passed to GroceryLinkBuilder at request time.
- locale_config.py: per-locale Amazon domain/dept config (already existed)
- grocery_links.py: GroceryLinkBuilder accepts locale=; routes Instacart to .ca
for Canada, uses amazon_domain per locale, Instacart/Walmart US/CA only
- settings.py: adds 'shopping_locale' to allowed settings keys
- shopping.py: reads locale from user's stored setting on all list/add/update paths
- SettingsView.vue: Shopping Region selector (NA, Europe, APAC, LATAM)
- stores/settings.ts: shoppingLocale reactive state, saves via settings API
Add GroceryLink schema model and grocery_links field to RecipeResult.
Introduce GroceryLinkBuilder service (Amazon Fresh, Walmart, Instacart)
using env-var affiliate tags; no links emitted when tags are absent.
Wire link builder into RecipeEngine.suggest() for levels 1-2.
Add test_grocery_links_free_tier to verify structure contract.
35 tests passing.
