推送真发送：webhook/slack 内置真实发送端 + worker 终态自动通知

此前订阅与分发框架都在，但分发端点传 sender=None，
webhook/slack 永远报无 sender、从未真发过。本轮：
- push：send_webhook/send_slack（标准库 urllib POST，
  单次 10 秒超时，不重试，失败记 errors）；sender=None
  时用内置端，显式 sender 优先；webpush/apns/fcm 仍报
  缺凭证（原因写明：webpush 需浏览器端三字段订阅与标准库
  没有的 P-256 ECDH + AES-GCM；apns 需 HTTP/2；fcm 需
  Firebase 服务账号，三者均无现成接收方，不造假发送）
- worker：run_one 终态（completed/failed，缺 key 与仓库
  失败两条早退路径也在内）后 best-effort 调分发，通知
  失败只记日志、绝不影响任务状态；取消（interrupted）
  不在事件集合里，不通知
- 测试：真实发送端 6 个（本地回环服务器）、worker 终态
  通知 2 个，旧无 sender 断言按新语义改写

cloud/worker.py

@@ -640,6 +640,34 @@ class Worker:
         except Exception:
             pass
 
+    def _notify_task_finished(self, task_id, project_id, event_type,
+                              error=None):
+        """任务终态推送：best-effort，绝不因通知失败影响任务状态。
+
+        只发 completed/failed（push.ALLOWED_PUSH_EVENTS 的子集；
+        interrupted 不在事件集合里，取消不通知）。无订阅时
+        dispatch 直接返回空 sent，不联网。同步发送、单次 10 秒
+        超时：慢订阅会拖住 worker 循环最多几秒，换取投递结果
+        可观测（失败记日志，不静默丢）；后台队列是后续优化，
+        不在本轮。
+        """
+        try:
+            from cloud.push import dispatch_event
+            result = dispatch_event(
+                self.db_path, event_type, project_id,
+                {"task_id": task_id, "status": event_type,
+                 "executor": self._executor_name(), "error": error})
+            if result.get("errors"):
+                log_event(self.logger, "worker_notify_failed",
+                          task_id=task_id, project_id=project_id,
+                          status=event_type,
+                          message="notify errors: %s" % (result["errors"],))
+        except Exception as exc:  # noqa: BLE001 -- 通知失败绝不炸任务
+            log_event(self.logger, "worker_notify_failed",
+                      task_id=task_id, project_id=project_id,
+                      status=event_type,
+                      message="notify exception: %s" % exc)
+
     # -- 认领 ----------------------------------------------------------
     def _budget_exceeded(self):
         return budget_exceeded(self.usage_turns, self.max_turns,
@@ -1346,6 +1374,8 @@ class Worker:
             self._audit(task["project_id"], "worker_missing_key", error)
             log_event(self.logger, "worker_missing_key", task_id=task_id,
                       project_id=task["project_id"], status="failed")
+            self._notify_task_finished(
+                task_id, task["project_id"], "failed", error=error)
             return {"dispatched": True, "task_id": task_id,
                     "host_name": self.executor._host_name(task)
                     if hasattr(self.executor, "_host_name") else task_id,
@@ -1365,6 +1395,8 @@ class Worker:
             self._audit(task["project_id"], "worker_repo_failed", repo_error)
             log_event(self.logger, "worker_repo_failed", task_id=task_id,
                       project_id=task["project_id"], status="failed")
+            self._notify_task_finished(
+                task_id, task["project_id"], "failed", error=repo_error)
             return {"dispatched": True, "task_id": task_id,
                     "host_name": self.executor._host_name(task)
                     if hasattr(self.executor, "_host_name") else task_id,
@@ -1537,6 +1569,9 @@ class Worker:
                       else "worker_failed",
                       task_id=task_id, project_id=task["project_id"],
                       status=final)
+            if final in ("completed", "failed"):
+                self._notify_task_finished(
+                    task_id, task["project_id"], final, error=error)
         else:
             # 已被取消/回收：DB 状态以 interrupted 为准，不再
             # 补一条 worker_completed/failed 审计误导排查。