fix(e2e): resolve lint error, Dashboard auth gap, and mock auth redirect

- Remove unused `response` variable in j8-unauth-access.spec.ts:40
- Move Dashboard route inside ProtectedRoute wrapper in App.tsx
- Add VITE_MOCK_AUTH mode to ProtectedRoute: check Zustand
  isAuthenticated flag instead of calling authClient.useSession()

Co-Authored-By: Paperclip <noreply@paperclip.ing>

e2e/journeys/j8-unauth-access.spec.ts

@@ -37,7 +37,7 @@ test.describe('J8: Unauthenticated Access', () => {
   test('shows loading spinner while auth session is pending', async ({ page }) => {
     // Intercept but don't respond — session stays pending
     await page.context().clearCookies();
-    const response = await page.request.fetch('/api/auth/session', {
+    await page.request.fetch('/api/auth/session', {
       method: 'GET',
     });