Issue #345: activity stack polish

The cross sits at the right edge of its row (the name's area kept only
the text's width, so the cross followed short names). Seen in the
running app; a test pins it.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

crates/ui-egui/src/panels/activity.rs

@@ -115,7 +115,8 @@ fn row(ui: &mut egui::Ui, t: &Tokens, task: &TaskInfo, width: f32) -> bool {
             let cross = task.cancellable && !task.cancelling;
             let label_w = if cross { width - CROSS - 6.0 } else { width };
             ui.allocate_ui_with_layout(vec2(label_w, 18.0), Layout::left_to_right(Align::Center), |ui| {
-                ui.set_max_width(label_w);
+                // the whole width, so the cross lands at the right edge however short the name
+                ui.set_width(label_w);
                 ui.add(egui::Label::new(RichText::new(tr(&task.label)).font(t.font(12.5)).color(t.text)).truncate());
             });
             if cross {

crates/ui-egui/src/tests_activity.rs

@@ -131,6 +131,16 @@ fn long_detail_stays_inside_the_stack() {
     assert!(row.width() <= WIDTH + 1.0, "{row:?}");
 }
 
+#[test]
+fn cross_sits_at_the_right_edge_of_its_row() {
+    let mut h = demo();
+    let g = h.app.session.activity.start("export", "Exporting", Cancel::Yes);
+    wait_visible(&mut h);
+    let row = rect(&h, &format!("activity:row:{}", g.id()));
+    let cross = rect(&h, &format!("activity:cancel:{}", g.id()));
+    assert!(cross.right() >= row.right() - 2.0, "the cross is at the right, not after the label: {cross:?} in {row:?}");
+}
+
 #[test]
 fn quit_with_a_running_task_asks_and_quit_anyway_cancels() {
     let mut h = demo();
@@ -184,7 +194,6 @@ fn start_export(h: &mut Headless, n: usize) {
     }
     let r = h.request("ui.dialog.confirm", json!({}), T);
     assert_eq!(r["ok"], true, "{r}");
-    assert!(h.app.export.is_some(), "running in the background");
 }
 
 #[test]
@@ -192,6 +201,7 @@ fn export_shows_a_row_and_stops_on_activity_cancel() {
     let mut h = demo();
     h.app.services.write_shared = Some(slow_writer(200));
     start_export(&mut h, 5);
+    assert!(h.app.export.is_some(), "running in the background");
     let tasks = h.request("ui.inspect", json!({}), T)["result"]["activity"].clone();
     assert_eq!(tasks[0]["kind"], "export", "{tasks}");
     assert_eq!(tasks[0]["total"], 5, "{tasks}");