feat: Python/Java SDK 接入清单与打包文档

对真实 nixmsg 跑 DEVELOPMENT 第 9 节接入清单（跳过仅 JS 跨域），补 README/示例，并修 Paho/HiveMQ 真机联调死锁与鉴权分类。

sdk/python/tests/test_client.py

@@ -67,7 +67,7 @@ class FakeTransportTests(unittest.TestCase):
             "send_at_ms": 1,
         }
         tr.inject_down(dumps(msg))
-        time.sleep(0.1)
+        time.sleep(0.3)
         self.assertEqual(delivered, ["m1"])
         # 找 ack 帧
         acks = [json.loads(p.decode()) for _, p in tr.publishes if json.loads(p.decode()).get("type") == "ack"]
@@ -75,7 +75,7 @@ class FakeTransportTests(unittest.TestCase):
 
         before = len(tr.publishes)
         tr.inject_down(dumps(msg))  # 已确认再到达
-        time.sleep(0.1)
+        time.sleep(0.3)
         self.assertEqual(delivered, ["m1"])  # 不重复交应用
         acks2 = [json.loads(p.decode()) for _, p in tr.publishes[before:] if json.loads(p.decode()).get("type") == "ack"]
         self.assertGreaterEqual(len(acks2), 1)  # 再 ack