feat(job): D1 Job 阶段上报（v3 §23）+ 列表/取消端点

- ResearchService.run_backtest/run_factor_test 支持 on_stage 回调（data_loading →
  factor_calculation/backtesting → analysis）；job_executor 经独立短会话把 stage 写库
  （子进程模式同样走 DB），收尾回读最后阶段避免覆盖
- /api/jobs：GET 列表（kind/limit）、POST /{id}/cancel（queued/running → CANCELLED +
  终止子进程 terminate_active；父进程兜底已跳过 CANCELLED）
- SSE /jobs/{id}/events 现会携带 stage
- tests/test_job_stages.py：成功 job 终态 stage=analysis；executor 取消 queued/幂等/
  已完成不可取消；API 列表+终态不可取消+404；全量 pytest 通过

backend/app/quant/service.py

@@ -120,17 +120,29 @@ class ResearchService:
         self._engine = engine
         self._index_repo = index_repo
 
-    def run_factor_test(self, spec: ResearchSpec, horizon_days: int = 21) -> FactorTestReport:
+    def run_factor_test(
+        self, spec: ResearchSpec, horizon_days: int = 21, on_stage=None
+    ) -> FactorTestReport:
+        """on_stage(str)：执行阶段回调（data_loading / factor_calculation / analysis），
+        供 Job 状态机上报 stage（v3 §23）。"""
         if spec.type != "factor_test":
             raise ValueError("factor_test 用例需要 spec.type=factor_test")
+        _stage(on_stage, "data_loading")
         daily = self._load_daily(spec)
-        return self._engine.run_factor_test(daily, spec, horizon_days=horizon_days)
+        _stage(on_stage, "factor_calculation")
+        report = self._engine.run_factor_test(daily, spec, horizon_days=horizon_days)
+        _stage(on_stage, "analysis")
+        return report
 
-    def run_backtest(self, spec: ResearchSpec) -> BacktestResult:
+    def run_backtest(self, spec: ResearchSpec, on_stage=None) -> BacktestResult:
         if spec.type != "backtest":
             raise ValueError("backtest 用例需要 spec.type=backtest")
+        _stage(on_stage, "data_loading")
         daily = self._load_daily(spec)
-        return self._engine.run_backtest(daily, spec)
+        _stage(on_stage, "backtesting")
+        result = self._engine.run_backtest(daily, spec)
+        _stage(on_stage, "analysis")
+        return result
 
     def run_factor_correlation(self, spec: ResearchSpec) -> FactorCorrelationReport:
         """多因子两两相关（v3 §12）：同 universe/period 装配 → 横截面相关矩阵。"""
@@ -158,3 +170,8 @@ class ResearchService:
             sorted(required),
             adjust=spec.price_adjustment,
         )
+
+
+def _stage(cb, name: str) -> None:
+    if cb is not None:
+        cb(name)