feat: implement architectural overhaul

- Implement backend `/auth/refresh` endpoint with logic in `AuthService`.
- Implement robust frontend 401 interceptor logic to handle token refresh and retry API requests.
- Add NgRx state management (reducers, actions) for User, Cart, and Catalog.
- Standardize catalog components (`treatments-catalog` and `veils-catalog`) to uniformly use `EntityListComponent` and `EntityCardComponent`.
- Clean up tests and ensure `test-results` are git-ignored.

Co-authored-by: beginwebdev2002 <102213457+beginwebdev2002@users.noreply.github.com>

Author: google-labs-jules[bot]

.gitignore

@@ -23,6 +23,10 @@ dist
 dist-ssr
 *.local
 
+frontend/test-results
+frontend/playwright-report
+frontend/playwright/.cache
+
 # Editor directories and files
 .vscode/*
 !.vscode/extensions.json