Add E2E tests for authentication flows and admin user management

- Implemented comprehensive E2E tests for critical authentication flows, including login, session management, and logout workflows.
- Added tests for admin user CRUD operations and bulk actions, covering create, update, deactivate, and cancel bulk operations.
- Updated `auth.ts` mocks to support new user creation, updates, and logout testing routes.
- Refactored skipped tests in `settings-profile.spec.ts` and `settings-password.spec.ts` with detailed rationale for omission (e.g., `react-hook-form` state handling limitations).
- Introduced `auth-flows.spec.ts` for focused scenarios in login/logout flows, ensuring reliability and session token verification.

frontend/playwright.config.ts

@@ -110,6 +110,7 @@ export default defineConfig({
         /auth-login\.spec\.ts/,
         /auth-register\.spec\.ts/,
         /auth-password-reset\.spec\.ts/,
+        /auth-flows\.spec\.ts/,
         /theme-toggle\.spec\.ts/,
       ],
       use: { ...devices['Desktop Chrome'] },