- Introduced a new `AuthContext` with Dependency Injection to replace direct `useAuthStore` access, enhancing E2E testability.
- Migrated authentication core components (`AuthInitializer`, `AuthGuard`, `Header`) and hooks (`useAuth`, `useUser`) to use `AuthContext`.
- Updated test suite:
- Refactored unit tests to mock `AuthContext` instead of `useAuthStore`.
- Enhanced E2E test helpers to inject mock auth stores for authenticated and admin scenarios.
- Verified API client interceptors remain compatible with the new setup.
- No breaking changes; maintained 98.38% test coverage.
