feat: implement FastAPI router, web + local UI updates, and metadata monitoring for the edge node

drb-edge-node/app/routers/ui.py

@@ -5,8 +5,14 @@ from fastapi.responses import HTMLResponse
 router = APIRouter(tags=["ui"])
 
 _TEMPLATE = Path(__file__).parent.parent / "templates" / "index.html"
+_SCANNER_TEMPLATE = Path(__file__).parent.parent / "templates" / "scanner.html"
 
 
 @router.get("/", response_class=HTMLResponse)
 async def index():
     return _TEMPLATE.read_text()
+
+
+@router.get("/scanner", response_class=HTMLResponse)
+async def scanner():
+    return _SCANNER_TEMPLATE.read_text()