feat(ui): confirm before closing a running ConPTY session

The tile's own X killed a live Claude session with no confirmation, unlike
the semantically similar Abandon-run action. Gate the close behind the same
ConfirmAsync mechanism, but only when Terminal.IsRunning -- a dead session
(StartError or exited-after-startup) still closes immediately since the X
there is pure cleanup.

src/ClaudeDo.Localization/locales/de.json

@@ -380,6 +380,7 @@
     "focusMode": "Fokus",
     "overviewMode": "Übersicht",
     "closeSession": "Sitzung beenden",
+    "closeSessionConfirm": "Laufende Sitzung beenden? Der Claude-Prozess wird abgebrochen.",
     "conptyLaunchFailed": "Interaktive Sitzung konnte nicht geöffnet werden: {0}",
     "conptyStarting": "Sitzung wird gestartet…",
     "conptyExited": "Sitzung beendet (Code {0}).",

src/ClaudeDo.Localization/locales/en.json

@@ -380,6 +380,7 @@
     "focusMode": "Focus",
     "overviewMode": "Overview",
     "closeSession": "Kill session",
+    "closeSessionConfirm": "End the running session? The Claude process will be aborted.",
     "conptyLaunchFailed": "Couldn't open interactive session: {0}",
     "conptyStarting": "Starting session…",
     "conptyExited": "Session ended (code {0}).",

src/ClaudeDo.Ui/ViewModels/MissionControlViewModel.cs

@@ -449,7 +449,7 @@ public sealed partial class MissionControlViewModel : ViewModelBase, IDisposable
     private void AddConPtyPane(ConPtyPaneViewModel pane)
     {
         pane.ErrorReported += OnConPtyPaneError;
-        pane.CloseRequested += CloseConPtySession;
+        pane.CloseRequested += OnPaneCloseRequested;
         pane.SubmitForReviewRequested += OnPaneSubmitForReview;
         pane.SessionDiedAfterStartup += OnPaneSessionDied;
         pane.AbandonRunRequested += OnPaneAbandonRun;
@@ -543,11 +543,27 @@ public sealed partial class MissionControlViewModel : ViewModelBase, IDisposable
         }
     }
 
+    // The tile's own X: a reflex click must not silently kill a live session the way it would a
+    // regular window. Confirm only when the terminal is actually running -- a dead one (StartError,
+    // or HasExited i.e. the #290 exited banner) is pure cleanup and closes straight away, same as it
+    // always did. Every other close path (handoff replacing a pane, submit-for-review, abandon-run)
+    // still calls CloseConPtySession directly and is unaffected.
+    private async void OnPaneCloseRequested(ConPtyPaneViewModel pane)
+    {
+        if (pane.Terminal.IsRunning)
+        {
+            if (ConfirmAsync is null) return;
+            if (!await ConfirmAsync(Loc.T("missionControl.closeSessionConfirm"))) return;
+        }
+
+        CloseConPtySession(pane);
+    }
+
     private void CloseConPtySession(ConPtyPaneViewModel pane)
     {
         if (!ConPtySessions.Contains(pane)) return;
         pane.ErrorReported -= OnConPtyPaneError;
-        pane.CloseRequested -= CloseConPtySession;
+        pane.CloseRequested -= OnPaneCloseRequested;
         pane.SubmitForReviewRequested -= OnPaneSubmitForReview;
         pane.SessionDiedAfterStartup -= OnPaneSessionDied;
         pane.AbandonRunRequested -= OnPaneAbandonRun;
@@ -601,7 +617,7 @@ public sealed partial class MissionControlViewModel : ViewModelBase, IDisposable
         foreach (var c in ConPtySessions.ToList())
         {
             c.ErrorReported -= OnConPtyPaneError;
-            c.CloseRequested -= CloseConPtySession;
+            c.CloseRequested -= OnPaneCloseRequested;
             c.SubmitForReviewRequested -= OnPaneSubmitForReview;
             c.SessionDiedAfterStartup -= OnPaneSessionDied;
             c.AbandonRunRequested -= OnPaneAbandonRun;

tests/ClaudeDo.Ui.Tests/ViewModels/MissionControlViewModelTests.cs

@@ -1072,4 +1072,59 @@ public class MissionControlViewModelTests : IDisposable
         Assert.Equal(new[] { "t1", "t2" }, worker.Cancelled);
         Assert.Empty(vm.ConPtySessions);
     }
+
+    // The tile's own X must not silently kill a live session -- a reflex click on a running pane
+    // has to go through the same confirm mechanism as Abandon Run.
+    [Fact]
+    public async Task Close_RunningSession_ConfirmDeclined_LeavesSessionOpen()
+    {
+        var worker = new FakeWorker();
+        using var vm = BuildVm(worker);
+        await vm.OpenConPtySessionAsync("t1");
+        var pane = vm.ConPtySessions[0];
+        pane.Terminal.IsRunning = true;
+        string? confirmMessage = null;
+        vm.ConfirmAsync = msg => { confirmMessage = msg; return Task.FromResult(false); };
+
+        pane.CloseCommand.Execute(null);
+        await Task.Delay(20);
+
+        Assert.NotNull(confirmMessage);
+        Assert.Single(vm.ConPtySessions);
+    }
+
+    [Fact]
+    public async Task Close_RunningSession_ConfirmAccepted_ClosesPane()
+    {
+        var worker = new FakeWorker();
+        using var vm = BuildVm(worker);
+        await vm.OpenConPtySessionAsync("t1");
+        var pane = vm.ConPtySessions[0];
+        pane.Terminal.IsRunning = true;
+        vm.ConfirmAsync = _ => Task.FromResult(true);
+
+        pane.CloseCommand.Execute(null);
+        await Task.Delay(20);
+
+        Assert.Empty(vm.ConPtySessions);
+    }
+
+    // A dead session (start failure or exited-after-startup) is pure cleanup -- no confirm needed.
+    [Fact]
+    public async Task Close_DeadSession_ClosesWithoutConfirming()
+    {
+        var worker = new FakeWorker();
+        using var vm = BuildVm(worker);
+        await vm.OpenConPtySessionAsync("t1");
+        var pane = vm.ConPtySessions[0];
+        pane.Terminal.ReportStartFailure("boom");
+        var confirmCalled = false;
+        vm.ConfirmAsync = _ => { confirmCalled = true; return Task.FromResult(true); };
+
+        pane.CloseCommand.Execute(null);
+        await Task.Delay(20);
+
+        Assert.False(confirmCalled);
+        Assert.Empty(vm.ConPtySessions);
+    }
 }