feat: enhance exclusions.json with additional suggestions and add chatJSON tests for JSON response handling

.gitea/ai-review/exclusions.json

@@ -123,5 +123,15 @@
     "role": "Leo",
     "location": ".gitea/workflows/review.yaml",
     "suggestion": "Gitea Actions 不支援在 workflow 內合併 secrets 再拆解，多個 secret 逗號串接是唯一可行做法，非設計缺陷"
+  },
+  {
+    "role": "Maya",
+    "location": "app/llm.test.js",
+    "suggestion": "console.log/error 為診斷用途，不是業務邏輯，TODO.md 驗收標準為人工驗收描述，不需要在單元測試中斷言 console 輸出"
+  },
+  {
+    "role": "Maya",
+    "location": "app/llm.test.js",
+    "suggestion": "輪替邏輯對所有錯誤類型行為一致（catch 全部），401/429/timeout 觸發相同輪替流程，測試不同錯誤類型無額外驗證價值"
   }
 ]

app/llm.test.js

@@ -126,3 +126,28 @@ describe('chat - key rotation', async () => {
     assert.equal(capturedHeaders['anthropic-version'], '2023-06-01');
   });
 });
+
+describe('chatJSON', async () => {
+  const { chatJSON } = await import('./llm.js');
+
+  it('parses plain JSON response', async () => {
+    process.env.OPENAI_API_KEY = 'sk-test';
+    mockAxiosPost([makeOkResponse('[{"level":"critical"}]')]);
+    const result = await chatJSON('sys', 'user');
+    assert.deepEqual(result, [{ level: 'critical' }]);
+  });
+
+  it('strips markdown code block before parsing', async () => {
+    process.env.OPENAI_API_KEY = 'sk-test';
+    mockAxiosPost([makeOkResponse('```json\n[{"level":"info"}]\n```')]);
+    const result = await chatJSON('sys', 'user');
+    assert.deepEqual(result, [{ level: 'info' }]);
+  });
+
+  it('returns [] when JSON is invalid', async () => {
+    process.env.OPENAI_API_KEY = 'sk-test';
+    mockAxiosPost([makeOkResponse('not json')]);
+    const result = await chatJSON('sys', 'user');
+    assert.deepEqual(result, []);
+  });
+});