Rebuild and expand E2E tests for Settings flows

- Updated Playwright config to enable 8 workers locally while maintaining single worker on CI.
- Rebuilt Settings Navigation E2E tests to verify page transitions and default redirects.
- Reintroduced Password Change E2E tests to validate form display and interactions.
- Expanded Profile Settings E2E tests to include email read-only verification.
- Marked Sessions Management E2E tests as skipped, pending route implementation confirmation.

frontend/e2e/settings-sessions.spec.ts

@@ -1,23 +1,20 @@
 /**
  * E2E Tests for Sessions Management Page
  *
- * DELETED: All 12 tests were failing due to auth state loss on navigation.
- * These tests will be rebuilt in Phase 3 with a focus on user behavior
- * and using the simplified auth architecture.
+ * SKIPPED: Tests fail because /settings/sessions route redirects to login.
+ * This indicates either:
+ * 1. The route doesn't exist in the current implementation
+ * 2. The route has different auth requirements
+ * 3. The route needs to be implemented
  *
- * Tests to rebuild:
- * - User can view active sessions
- * - User can revoke a non-current session
- * - User cannot revoke current session
- * - Bulk revoke confirmation dialog
+ * These tests should be re-enabled once the sessions page is confirmed to exist.
  */
 
-import { test, expect } from '@playwright/test';
-import { setupAuthenticatedMocks } from './helpers/auth';
+import { test } from '@playwright/test';
 
 test.describe('Sessions Management', () => {
-  test.skip('Placeholder - tests will be rebuilt in Phase 3', async ({ page }) => {
-    // Tests deleted during nuclear refactor
-    // Will be rebuilt with simplified auth architecture
+  test.skip('Placeholder - route /settings/sessions redirects to login', async () => {
+    // Tests skipped because navigation to /settings/sessions fails auth
+    // Verify route exists before re-enabling these tests
   });
 });