Add Pydantic models and FastAPI router structure for agent and backend

agent/app/routers/services.py

@@ -0,0 +1,42 @@
+from datetime import datetime, timezone
+from typing import Literal
+
+from fastapi import APIRouter, HTTPException
+
+from app.config import settings
+from app.models import ServiceActionResponse, ServiceListResponse, ServiceState
+from app.services.systemd_manager import SystemdManager
+
+router = APIRouter(prefix='/services', tags=['services'])
+manager = SystemdManager()
+
+
+@router.get('', response_model=ServiceListResponse)
+def list_services() -> ServiceListResponse:
+    items = manager.list_services(settings.monitored_services)
+    return ServiceListResponse(count=len(items), time=datetime.now(timezone.utc), items=items)
+
+
+@router.get('/{name}', response_model=ServiceState)
+def get_service(name: str) -> ServiceState:
+    items = manager.list_services([name])
+    if not items:
+        raise HTTPException(status_code=404, detail='Service not found')
+    return items[0]
+
+
+@router.post('/{name}/{action}', response_model=ServiceActionResponse)
+def service_action(name: str, action: Literal['start', 'stop', 'restart']) -> ServiceActionResponse:
+    if action == 'start':
+        manager.start(name)
+    elif action == 'stop':
+        manager.stop(name)
+    elif action == 'restart':
+        manager.restart(name)
+    return ServiceActionResponse(
+        status='accepted',
+        action=action,
+        service=name,
+        time=datetime.now(timezone.utc),
+        message=f'{action} requested',
+    )