fix(remoteingress-core): initialize disconnect reason only when set in hub loop break paths

rust/crates/remoteingress-core/src/hub.rs

@@ -735,7 +735,9 @@ async fn handle_edge_connection(
     // Single-owner I/O engine — no tokio::io::split, no mutex
     let mut tunnel_io = remoteingress_protocol::TunnelIo::new(tls_stream, Vec::new());
 
-    let mut disconnect_reason = "unknown".to_string();
+    // Assigned in every break path of the hub_loop before use at the end.
+    #[allow(unused_assignments)]
+    let mut disconnect_reason = String::new();
 
     'hub_loop: loop {
         // Drain completed stream cleanups from spawned tasks