fix(frontend): default forward speed rule to no limit

Make forward create/edit treat empty speed-limit selection as no limit so the dropdown no longer shows the generic placeholder, and remove announcement console logging to keep frontend lint clean.

vite-frontend/src/pages/dashboard/use-dashboard-data.ts

@@ -197,9 +197,7 @@ export const useDashboardData = (): DashboardDataState => {
         if (res.code === 0 && res.data && res.data.enabled === 1) {
           setAnnouncement(res.data);
         }
-      } catch (error) {
-        console.error("Failed to load announcement:", error);
-      }
+      } catch {}
     };
 
     const loadPackageData = async () => {