test: add opt-in panel e2e harness

tests/e2e/tests/panel.rs

@@ -0,0 +1,77 @@
+use std::time::Duration;
+
+use yoi_e2e::{FixtureWorkspace, KeyPress, PanelHarness, yoi_binary};
+
+#[test]
+fn panel_mouse_click_selects_row_without_dispatching_action() -> yoi_e2e::Result<()> {
+    let binary = yoi_binary();
+    let fixture = FixtureWorkspace::new(&binary)?;
+    let mut panel = PanelHarness::spawn(fixture.panel_config(binary))?;
+
+    let rows = panel.wait_for_rows(2)?;
+    let selected = rows.selected.clone();
+    let target = rows
+        .rows
+        .iter()
+        .find(|row| Some(&row.key) != selected.as_ref())
+        .cloned()
+        .expect("fixture should render a second selectable row");
+
+    let before_events = panel.events()?.len();
+    panel.click(&target)?;
+    panel.expect_selection(&target.key)?;
+
+    let events = panel.events()?;
+    assert!(
+        events[before_events..]
+            .iter()
+            .all(|event| event.event != "action_requested"),
+        "mouse selection must not dispatch panel actions; artifacts at {}",
+        panel.artifacts().dir.display()
+    );
+
+    panel.press(KeyPress::CtrlC)?;
+    let status = panel.expect_exit_within(PanelHarness::default_exit_wait())?;
+    assert!(status.success(), "panel should exit cleanly with Ctrl+C");
+    Ok(())
+}
+
+#[test]
+fn panel_ctrl_c_exits_promptly_after_background_barrier() -> yoi_e2e::Result<()> {
+    let binary = yoi_binary();
+    let fixture = FixtureWorkspace::new(&binary)?;
+    let mut panel = PanelHarness::spawn(fixture.panel_config(binary))?;
+
+    panel.wait_for("panel_ready", Duration::from_secs(5), |event| {
+        event.event == "panel_ready"
+    })?;
+    assert!(
+        panel
+            .events()?
+            .iter()
+            .any(|event| event.event == "background_task_started"),
+        "background task barrier was not observed; artifacts at {}",
+        panel.artifacts().dir.display()
+    );
+
+    let started = std::time::Instant::now();
+    panel.press(KeyPress::CtrlC)?;
+    let status = panel.expect_exit_within(PanelHarness::default_exit_wait())?;
+    let elapsed = started.elapsed();
+
+    assert!(status.success(), "panel should exit cleanly with Ctrl+C");
+    assert!(
+        elapsed <= PanelHarness::default_exit_wait(),
+        "quit latency {elapsed:?} exceeded threshold; artifacts at {}",
+        panel.artifacts().dir.display()
+    );
+    assert!(
+        panel
+            .events()?
+            .iter()
+            .any(|event| event.event == "quit_requested"),
+        "quit_requested observability event missing; artifacts at {}",
+        panel.artifacts().dir.display()
+    );
+    Ok(())
+}