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/tests/test_worker.py

@@ -126,6 +126,103 @@ class WorkerTestCase(unittest.TestCase):
         # B 的依赖未完成，始终不可派，保持 queued。
         self.assertEqual(_status(self.db_path, "B"), "queued")
 
+    # -- 终态推送 --------------------------------------------------------
+    def test_notify_on_completed_and_failed(self):
+        """任务终态自动通知订阅：completed 与 failed 各发一次真 POST
+        到本地回环 webhook，body 含事件类型与任务 id；取消
+        （interrupted）不在事件集合里，不通知（见下个测试）。"""
+        import http.server
+        import threading
+
+        requests = []
+
+        class Handler(http.server.BaseHTTPRequestHandler):
+            def do_POST(self):
+                length = int(self.headers.get("Content-Length") or 0)
+                body = self.rfile.read(length) if length else b""
+                requests.append(json.loads(body.decode("utf-8")))
+                self.send_response(200)
+                self.send_header("Content-Length", "2")
+                self.end_headers()
+                self.wfile.write(b"{}")
+
+            def log_message(self, *args):
+                pass
+
+        server = http.server.ThreadingHTTPServer(
+            ("127.0.0.1", 0), Handler)
+        thread = threading.Thread(
+            target=server.serve_forever, daemon=True)
+        thread.start()
+        try:
+            from cloud.push import create_subscription
+            url = "http://127.0.0.1:%d/hook" % server.server_address[1]
+            create_subscription(
+                self.db_path, "p1", "user-1", "webhook", url, "instant")
+            _insert_task(self.db_path, "A")
+            _insert_task(self.db_path, "B")
+
+            def failing(cmd):
+                if "dispatch" in cmd and cmd[cmd.index("--name") + 1] == "B":
+                    return SimpleNamespace(returncode=1, stdout="boom",
+                                           stderr="")
+                return _completed_runner(cmd)
+
+            worker = self._worker(runner=failing)
+            results = worker.run_all()
+            self.assertEqual(
+                sorted(r["status"] for r in results),
+                ["completed", "failed"])
+            by_task = {b["task_id"]: b for b in requests}
+            self.assertEqual(set(by_task), {"A", "B"})
+            self.assertEqual(by_task["A"]["event_type"], "completed")
+            self.assertEqual(by_task["B"]["event_type"], "failed")
+            self.assertIn("boom", json.dumps(by_task["B"]["payload"]))
+        finally:
+            server.shutdown()
+            server.server_close()
+            thread.join(timeout=5)
+
+    def test_cancel_does_not_notify(self):
+        """取消只标 interrupted，不在推送事件集合里，不发通知。"""
+        import http.server
+        import threading
+
+        requests = []
+
+        class Handler(http.server.BaseHTTPRequestHandler):
+            def do_POST(self):
+                length = int(self.headers.get("Content-Length") or 0)
+                self.rfile.read(length) if length else b""
+                requests.append(True)
+                self.send_response(200)
+                self.send_header("Content-Length", "2")
+                self.end_headers()
+                self.wfile.write(b"{}")
+
+            def log_message(self, *args):
+                pass
+
+        server = http.server.ThreadingHTTPServer(
+            ("127.0.0.1", 0), Handler)
+        thread = threading.Thread(
+            target=server.serve_forever, daemon=True)
+        thread.start()
+        try:
+            from cloud.push import create_subscription
+            url = "http://127.0.0.1:%d/hook" % server.server_address[1]
+            create_subscription(
+                self.db_path, "p1", "user-1", "webhook", url, "instant")
+            _insert_task(self.db_path, "A")
+            worker = self._worker(runner=_completed_runner)
+            self.assertTrue(worker.cancel("A"))
+            self.assertEqual(worker.run_all(), [])
+            self.assertEqual(requests, [])
+        finally:
+            server.shutdown()
+            server.server_close()
+            thread.join(timeout=5)
+
     # -- 取消 ------------------------------------------------------------
     def test_cancel_queued_task_marks_interrupted(self):
         _insert_task(self.db_path, "A")