gui: split host:port for manually-typed addresses

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

gui/src/main.rs

@@ -517,6 +517,7 @@ fn ServerCard(
     editing_index: Signal<Option<usize>>,
     overrides: Resource<ProxyOverrides>,
 ) -> Element {
+    let user_config = use_context::<ConfigSystem>();
     let net: Coroutine<Command> = use_coroutine_handle();
 
     let address = format!("{}:{}", server.address, server.port);
@@ -551,7 +552,9 @@ fn ServerCard(
                 class: "server-card__action server-card__action--connect",
                 onclick: {
                     let entry = connect_entry.clone();
+                    let user_config = user_config.clone();
                     move |_| {
+                        user_config.config_set("username", &entry.username);
                         net.send(Connect {
                             target: ConnectTarget::Direct {
                                 host: entry.address.clone(),