feat(ux): implement sprint 11 user experience module

docs/platform/06-api-contracts.md

@@ -50,6 +50,27 @@
   - Backend may introduce new sort IDs via bootstrap `catalog.availableSorts`.
   - Frontend must render unknown sort keys safely if label mapping is provided.
 
+  ## User Experience API Expectations (architecture-ready)
+  - Wishlist (authenticated mode, future-ready):
+    - GET /me/wishlist
+    - POST /me/wishlist
+    - DELETE /me/wishlist/{itemId}
+  - Compare list (optional sync for authenticated mode):
+    - GET /me/compare
+    - POST /me/compare
+    - DELETE /me/compare/{itemId}
+  - Saved searches:
+    - GET /me/saved-searches
+    - POST /me/saved-searches
+    - DELETE /me/saved-searches/{id}
+  - Recently viewed sync (optional):
+    - GET /me/recently-viewed
+    - POST /me/recently-viewed
+
+  Правила:
+  - Guest mode может хранить UX данные локально (local storage) без backend-запросов.
+  - UI не вызывает HttpClient напрямую: Feature -> Facade -> Repository/Provider.
+
 ## Пример API ответа: категории
 ```json
 {