feat(saleor): Phase 5 - Remove WooCommerce

- Remove @woocommerce/woocommerce-rest-api dependency
- Delete src/lib/woocommerce.ts
- Delete src/stores/cartStore.ts (replaced by saleorCheckoutStore)
- Clean up package.json dependencies
- Project now fully migrated to Saleor GraphQL API

package.json

@@ -10,7 +10,6 @@
   },
   "dependencies": {
     "@apollo/client": "^4.1.6",
-    "@woocommerce/woocommerce-rest-api": "^1.0.2",
     "clsx": "^2.1.1",
     "framer-motion": "^12.34.4",
     "graphql": "^16.13.1",