fix: CancelledError/Exception 경로에도 DB log_completion 추가

task.cancel()로 인한 CancelledError는 streaming loop 바깥에서
잡히므로 별도 log_completion 필요

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

nanoclaude/services/worker.py

@@ -83,9 +83,17 @@ async def run(job: Job) -> None:
     except asyncio.CancelledError:
         job_manager.set_status(job.id, JobStatus.cancelled)
         await state_stream.push(job.id, "error", {"message": "작업이 취소되었습니다."})
+        try:
+            await log_completion(job.id, "cancelled", 0, (time() - start_time) * 1000, time())
+        except Exception:
+            pass
     except Exception:
         logger.exception("Worker failed for job %s", job.id)
         job_manager.set_status(job.id, JobStatus.failed)
         await state_stream.push(job.id, "error", {"message": "내부 오류가 발생했습니다."})
+        try:
+            await log_completion(job.id, "failed", 0, (time() - start_time) * 1000, time())
+        except Exception:
+            pass
     finally:
         await state_stream.push_done(job.id)