test: 补充单元测试提升代码覆盖率

新增测试文件:
- agent/executor-extended.test.ts, presets/
- context/manager-extended.test.ts
- core/agent.test.ts, providers.test.ts
- lsp/cli.test.ts, client-extended.test.ts, index.test.ts
- permission/file-prompt.test.ts, prompt.test.ts
- skills/builtin/
- tools/filesystem/write_file-extended.test.ts
- tools/git/git_commit-extended.test.ts
- tools/load_description.test.ts
- tools/todo/todo-manager.test.ts
- tools/tool-search.test.ts
- types/
- utils/config-extended.test.ts, diff-extended.test.ts

修改现有测试:
- agent/manager.test.ts
- tools/skill/skill.test.ts
- utils/config.test.ts, diff.test.ts, image.test.ts

tests/unit/agent/manager.test.ts

@@ -251,5 +251,76 @@ describe('AgentManager - Agent 管理器', () => {
       // 这里只验证 cleanup 不会崩溃
       expect(true).toBe(true);
     });
+
+    it('使用默认 maxAge', async () => {
+      const agentId = await manager.runInBackground(
+        mockAgentInfo,
+        '任务',
+        '执行',
+        mockConfig,
+        {} as any,
+        mockContext
+      );
+
+      // 等待完成
+      await new Promise((r) => setTimeout(r, 300));
+
+      // 使用默认 maxAge（1 小时），不应该清理刚完成的
+      manager.cleanup();
+
+      // Agent 应该还在（因为未超过 1 小时）
+      const agent = manager.getAgent(agentId);
+      expect(agent).not.toBeNull();
+    });
+  });
+
+  describe('完成回调', () => {
+    it('多个等待者都收到通知', async () => {
+      const agentId = await manager.runInBackground(
+        mockAgentInfo,
+        '任务',
+        '执行',
+        mockConfig,
+        {} as any,
+        mockContext
+      );
+
+      // 并发等待
+      const [result1, result2] = await Promise.all([
+        manager.getAgentOutput(agentId, true, 5),
+        manager.getAgentOutput(agentId, true, 5),
+      ]);
+
+      expect(result1).not.toBeNull();
+      expect(result2).not.toBeNull();
+      expect(result1!.id).toBe(agentId);
+      expect(result2!.id).toBe(agentId);
+    });
+  });
+
+  describe('已完成 Agent 的阻塞查询', () => {
+    it('已完成的 Agent 阻塞查询立即返回', async () => {
+      const agentId = await manager.runInBackground(
+        mockAgentInfo,
+        '任务',
+        '执行',
+        mockConfig,
+        {} as any,
+        mockContext
+      );
+
+      // 等待完成
+      await manager.getAgentOutput(agentId, true, 5);
+
+      // 再次阻塞查询应立即返回
+      const startTime = Date.now();
+      const result = await manager.getAgentOutput(agentId, true, 10);
+      const elapsed = Date.now() - startTime;
+
+      expect(result).not.toBeNull();
+      expect(result!.status).not.toBe('running');
+      // 应该立即返回，不需要等 10 秒
+      expect(elapsed).toBeLessThan(1000);
+    });
   });
 });