feat(ui): add error field and red status line display

crates/k-launcher-ui/src/app.rs

@@ -26,6 +26,7 @@ pub struct KLauncherApp {
     results: Arc<Vec<SearchResult>>,
     selected: usize,
     cfg: AppearanceCfg,
+    error: Option<String>,
 }
 
 impl KLauncherApp {
@@ -41,6 +42,7 @@ impl KLauncherApp {
             results: Arc::new(vec![]),
             selected: 0,
             cfg,
+            error: None,
         }
     }
 }
@@ -55,6 +57,7 @@ pub enum Message {
 fn update(state: &mut KLauncherApp, message: Message) -> Task<Message> {
     match message {
         Message::QueryChanged(q) => {
+            state.error = None;
             state.query = q.clone();
             state.selected = 0;
             let engine = state.engine.clone();
@@ -186,7 +189,22 @@ fn view(state: &KLauncherApp) -> Element<'_, Message> {
         scrollable(column(result_rows).spacing(2).width(Length::Fill)).height(Length::Fill)
     };
 
-    let content = column![search_bar, results_list]
+    let maybe_error: Option<Element<'_, Message>> = state.error.as_ref().map(|msg| {
+        container(
+            text(msg.as_str())
+                .size(12.0)
+                .color(Color::from_rgba8(255, 80, 80, 1.0)),
+        )
+        .width(Length::Fill)
+        .padding([4, 12])
+        .into()
+    });
+
+    let mut content_children: Vec<Element<'_, Message>> = vec![search_bar.into(), results_list.into()];
+    if let Some(err) = maybe_error {
+        content_children.push(err);
+    }
+    let content = column(content_children)
         .spacing(8)
         .padding(12)
         .width(Length::Fill)