chore: Implement authentication fixes for TestDataManager and update user management tests

- Refactored TestDataManager to use authenticated context with Playwright's newContext method.
- Updated auth-fixtures to ensure proper authentication state is inherited for API requests.
- Created constants.ts to avoid circular imports and manage shared constants.
- Fixed critical bug in auth setup that caused E2E tests to fail due to improper imports.
- Re-enabled user management tests with updated selectors and added comments regarding current issues.
- Documented environment configuration issues causing cookie domain mismatches in skipped tests.
- Generated QA report detailing test results and recommendations for further action.

tests/constants.ts

@@ -0,0 +1,19 @@
+/**
+ * Shared test constants
+ *
+ * This file contains constants used across test files.
+ * Extracted to avoid circular imports with test setup files.
+ */
+
+import { fileURLToPath } from 'url';
+import { dirname, join } from 'path';
+
+const __filename = fileURLToPath(import.meta.url);
+const __dirname = dirname(__filename);
+
+/**
+ * Path to the authentication storage state file.
+ * Created by auth.setup.ts during the setup project phase.
+ * Used by browser contexts and API request contexts to inherit authentication.
+ */
+export const STORAGE_STATE = join(__dirname, '../playwright/.auth/user.json');