test: 补充 7 个缺失测试用例，覆盖所有 CAS 失败和只读路径

新增用例：
- markSucceeded CAS 失败（非终态 queued）→ JobNotActiveError
- markFailed CAS 失败（已终态）→ JobAlreadyTerminalError
- markFailed 接受可选 tx 参数
- extendLock CAS 失败（Job 不在 running）→ JobNotActiveError
- requestCancellation 终态 Job → JobNotCancellableError
- findExpiredLocks 过期锁查询
- findById 按 ID 查询
总测试数：43 → 50

Co-Authored-By: Claude <noreply@anthropic.com>

src/modules/ai-job/ai-job-lifecycle.repository.spec.ts

@@ -240,6 +240,16 @@ describe('AiJobLifecycleRepository', () => {
 
       await expect(repo.extendLock('job-001', 'worker-1')).rejects.toThrow(JobExtendLockError);
     });
+
+    it('续约失败（Job 不在 running 状态）抛出 JobNotActiveError', async () => {
+      (prisma.aiJob.updateMany as jest.Mock).mockResolvedValue({ count: 0 });
+      (prisma.aiJob.findUnique as jest.Mock).mockResolvedValue({
+        lifecycleStatus: 'succeeded', // terminal, not running
+        lockedBy: null,
+      });
+
+      await expect(repo.extendLock('job-001', 'worker-1')).rejects.toThrow(JobNotActiveError);
+    });
   });
 
   describe('markSucceeded', () => {
@@ -285,6 +295,15 @@ describe('AiJobLifecycleRepository', () => {
       expect(tx.aiJob.updateMany).toHaveBeenCalled();
       // 不应该调用 this.prisma
     });
+
+    it('CAS 失败（非终态，如 queued）抛出 JobNotActiveError', async () => {
+      (prisma.aiJob.updateMany as jest.Mock).mockResolvedValue({ count: 0 });
+      (prisma.aiJob.findUnique as jest.Mock).mockResolvedValue({
+        lifecycleStatus: 'queued', // not running, not terminal
+      });
+
+      await expect(repo.markSucceeded('job-001')).rejects.toThrow(JobNotActiveError);
+    });
   });
 
   describe('markFailed', () => {
@@ -316,6 +335,29 @@ describe('AiJobLifecycleRepository', () => {
       );
       expect(result.lifecycleStatus).toBe('failed');
     });
+
+    it('CAS 失败（已终态）抛出 JobAlreadyTerminalError', async () => {
+      (prisma.aiJob.updateMany as jest.Mock).mockResolvedValue({ count: 0 });
+      (prisma.aiJob.findUnique as jest.Mock).mockResolvedValue({
+        lifecycleStatus: 'succeeded',
+      });
+
+      await expect(
+        repo.markFailed('job-001', { errorCode: 'TEST' }),
+      ).rejects.toThrow(JobAlreadyTerminalError);
+    });
+
+    it('接受可选 tx 参数，复用调用方事务', async () => {
+      tx.aiJob.updateMany.mockResolvedValue({ count: 1 });
+      tx.aiJob.findUniqueOrThrow.mockResolvedValue({
+        id: 'job-001',
+        lifecycleStatus: 'failed',
+        errorCode: 'PROVIDER_TIMEOUT',
+      });
+
+      await repo.markFailed('job-001', { errorCode: 'PROVIDER_TIMEOUT' }, tx);
+      expect(tx.aiJob.updateMany).toHaveBeenCalled();
+    });
   });
 
   describe('markCancelled', () => {
@@ -405,6 +447,12 @@ describe('AiJobLifecycleRepository', () => {
 
       await expect(repo.requestCancellation('job-001')).rejects.toThrow(JobNotCancellableError);
     });
+
+    it('终态 Job 不可取消 → 抛出 JobNotCancellableError', async () => {
+      (prisma.aiJob.findUnique as jest.Mock).mockResolvedValue({ lifecycleStatus: 'succeeded' });
+
+      await expect(repo.requestCancellation('job-001')).rejects.toThrow(JobNotCancellableError);
+    });
   });
 
   describe('findByLifecycleStatus', () => {
@@ -424,4 +472,31 @@ describe('AiJobLifecycleRepository', () => {
       );
     });
   });
+
+  describe('findExpiredLocks', () => {
+    it('查找锁过期的 running Job', async () => {
+      (prisma.aiJob.findMany as jest.Mock).mockResolvedValue([]);
+
+      await repo.findExpiredLocks(90000);
+      expect(prisma.aiJob.findMany).toHaveBeenCalledWith(
+        expect.objectContaining({
+          where: {
+            lifecycleStatus: 'running',
+            lockUntil: { lt: expect.any(Date) },
+          },
+        }),
+      );
+    });
+  });
+
+  describe('findById', () => {
+    it('按 ID 查找 Job', async () => {
+      const mockJob = { id: 'job-001', lifecycleStatus: 'queued' };
+      (prisma.aiJob.findUnique as jest.Mock).mockResolvedValue(mockJob);
+
+      const result = await repo.findById('job-001');
+      expect(prisma.aiJob.findUnique).toHaveBeenCalledWith({ where: { id: 'job-001' } });
+      expect(result).toEqual(mockJob);
+    });
+  });
 });