Fix cargo fmt formatting in metrics module

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: haasonsaas

src/server/metrics.rs

@@ -126,7 +126,10 @@ pub async fn get_metrics(State(state): State<Arc<AppState>>) -> impl IntoRespons
     );
 
     (
-        [(axum::http::header::CONTENT_TYPE, "text/plain; charset=utf-8")],
+        [(
+            axum::http::header::CONTENT_TYPE,
+            "text/plain; charset=utf-8",
+        )],
         buf,
     )
 }