gui: split host:port for manually-typed addresses

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

gui/src/main.rs

@@ -923,6 +923,13 @@ fn AddServerModal(on_save: EventHandler<ServerEntry>, on_cancel: EventHandler<()
                                 address.set(evt.value());
                             }
                         },
+                        onblur: move |_| {
+                            let (host, maybe_port) = split_host_port(&address.read());
+                            if let Some(p) = maybe_port {
+                                address.set(host);
+                                port.set(p);
+                            }
+                        },
                         required: true,
                     }
                     div {
@@ -1064,6 +1071,13 @@ fn EditServerModal(
                                 address.set(evt.value());
                             }
                         },
+                        onblur: move |_| {
+                            let (host, maybe_port) = split_host_port(&address.read());
+                            if let Some(p) = maybe_port {
+                                address.set(host);
+                                port.set(p);
+                            }
+                        },
                         required: true,
                     }
                     div {