[JUNE 25] Permanent failover to Flash model for OAuth users after persistent 429 errors (#1376)

Co-authored-by: Scott Densmore <scottdensmore@mac.com>

packages/cli/src/ui/App.test.tsx

@@ -125,6 +125,7 @@ vi.mock('@gemini-cli/core', async (importOriginal) => {
         getGeminiClient: vi.fn(() => ({})),
         getCheckpointingEnabled: vi.fn(() => opts.checkpointing ?? true),
         getAllGeminiMdFilenames: vi.fn(() => ['GEMINI.md']),
+        setFlashFallbackHandler: vi.fn(),
       };
     });
   return {