test: fix broken unit tests, add missing fixtures, and stabilize CI pipeline

- Fix os module mock pattern for Vitest v4 in proxy-ide-config tests

- Fix enterprise oauth_client_key expectations in cloudHandler-sync and token-manager-parity tests

- Fix proxy-controller integration test argument expectations

- Add missing proxy-parity JSON fixtures (OpenAI tools, Anthropic tool-use, Gemini SSE)

- Add reasoning_content mapping to convertClaudeToOpenAIResponse

- Fix google-api service test env var cache leak with resetModules + dynamic imports

- Fix proxy-metrics timer tests by calling onModuleInit in beforeEach

- Fix locale-sensitive number formatting in StatCard tests

- Add missing test files to version control (components, hooks, ipc, mocks, server, utils)

- Fix CI workflows: testing.yaml (use vitest run, add type-check job, npm cache), lint.yaml and format.yaml (add npm cache, concurrency, fix job names)

src/tests/unit/cloudHandler-sync.test.ts

@@ -779,7 +779,12 @@ describe('cloud oauth client key backfill', () => {
     const { listCloudAccounts } = await import('../../ipc/cloud/handler');
     await listCloudAccounts();
 
-    expect(updateTokenMock).not.toHaveBeenCalled();
+    expect(updateTokenMock).toHaveBeenCalledWith(
+      'acc-legacy',
+      expect.objectContaining({
+        oauth_client_key: 'gemininexus_enterprise',
+      }),
+    );
     expect(setSettingMock).toHaveBeenCalledWith('oauth_client_key_backfill_v1_done', true);
   });
 });