feat(channel-service): add Python FastAPI pywechat channel service

- Add FastAPI project under channel-service/
- Implement mock pywechat client adapter (login, send, heartbeat)
- Add /v1/wechat-personal/login/*, /v1/wechat-personal/send/* APIs
- Add /v1/heartbeat and /v1/monitor/status for client health
- Add /monitor HTML page with Web Components
- Add pytest suite and Dockerfile
- Update .gitignore for Python/Node artifacts

channel-service/tests/conftest.py

@@ -0,0 +1,4 @@
+import os
+import sys
+
+sys.path.insert(0, os.path.abspath(os.path.join(os.path.dirname(__file__), "..")))

channel-service/tests/test_api.py

@@ -0,0 +1,70 @@
+from fastapi.testclient import TestClient
+
+from app.main import app
+
+client = TestClient(app)
+
+
+def test_health():
+    response = client.get("/health")
+    assert response.status_code == 200
+    assert response.json()["status"] == "ok"
+
+
+def test_login_flow():
+    r = client.post("/v1/wechat-personal/login/start", json={"account_id": "bot-001", "account_name": "测试号"})
+    assert r.status_code == 200
+    body = r.json()
+    assert body["login_id"]
+    assert body["qr_code_url"]
+
+    r = client.get("/v1/wechat-personal/login/bot-001/status")
+    assert r.status_code == 200
+    assert r.json()["login_status"] == "pending"
+
+    r = client.post("/v1/wechat-personal/login/bot-001/confirm")
+    assert r.status_code == 200
+    assert r.json()["success"] is True
+
+    r = client.get("/v1/wechat-personal/login/bot-001/status")
+    assert r.json()["login_status"] == "success"
+    assert r.json()["online_status"] == "online"
+
+
+def test_send_after_login():
+    client.post("/v1/wechat-personal/login/start", json={"account_id": "bot-002"})
+    client.post("/v1/wechat-personal/login/bot-002/confirm")
+
+    r = client.post("/v1/wechat-personal/send/text", json={
+        "account_id": "bot-002",
+        "conversation_id": "room-001",
+        "text": "hello"
+    })
+    assert r.status_code == 200
+    assert r.json()["success"] is True
+    assert r.json()["message_id"]
+
+
+def test_send_without_login_fails():
+    r = client.post("/v1/wechat-personal/send/text", json={
+        "account_id": "bot-offline",
+        "conversation_id": "room-001",
+        "text": "hello"
+    })
+    assert r.status_code == 200
+    assert r.json()["success"] is False
+
+
+def test_heartbeat_and_monitor():
+    client.post("/v1/heartbeat", json={"account_id": "bot-003", "risk_level": 10, "sent_count_today": 5})
+    r = client.get("/v1/monitor/status")
+    assert r.status_code == 200
+    clients = r.json()["clients"]
+    assert len(clients) >= 1
+    assert any(c["account_id"] == "bot-003" and c["risk_level"] == 10 for c in clients)
+
+
+def test_monitor_page():
+    r = client.get("/monitor")
+    assert r.status_code == 200
+    assert "channel-status-table" in r.text