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/app/api/wechat_personal.py

@@ -0,0 +1,53 @@
+from __future__ import annotations
+
+from typing import Optional
+
+from fastapi import APIRouter
+from pydantic import BaseModel, Field
+
+from app.services.login_service import login_service
+from app.services.send_service import send_service
+
+router = APIRouter(prefix="/v1/wechat-personal", tags=["wechat-personal"])
+
+
+class StartLoginRequest(BaseModel):
+    account_id: str = Field(..., description="渠道账号唯一标识")
+    account_name: Optional[str] = Field(None, description="账号显示名称")
+
+
+class SendTextRequest(BaseModel):
+    account_id: str
+    conversation_id: str = Field(..., description="目标会话/群 ID")
+    text: str = Field(..., min_length=1, description="消息内容")
+
+
+class SendImageRequest(BaseModel):
+    account_id: str
+    conversation_id: str
+    image_url: str
+
+
+@router.post("/login/start")
+def start_login(request: StartLoginRequest):
+    return login_service.start_login(request.account_id, request.account_name)
+
+
+@router.get("/login/{account_id}/status")
+def login_status(account_id: str):
+    return login_service.get_status(account_id)
+
+
+@router.post("/login/{account_id}/confirm")
+def confirm_login(account_id: str):
+    return login_service.confirm_login(account_id)
+
+
+@router.post("/send/text")
+def send_text(request: SendTextRequest):
+    return send_service.send_text(request.account_id, request.conversation_id, request.text)
+
+
+@router.post("/send/image")
+def send_image(request: SendImageRequest):
+    return send_service.send_image(request.account_id, request.conversation_id, request.image_url)