fix(claude-do): merge ConPTY tiles: deliver AltGr characters (@, \, {, }, €, …) as

ClaudeDo-Task: 4abf8b93e1d94c98b122521a8b850a77

src/ClaudeDo.Ui/Views/InteractiveTerminalView.axaml.cs

@@ -40,6 +40,15 @@ public partial class InteractiveTerminalView : UserControl
 
     private void OnPreviewKeyDown(object? sender, KeyEventArgs e)
     {
+        // AltGr arrives as Ctrl+Alt; the library would turn it into a control sequence (and mark it handled).
+        if (IsAltGrText(e.KeyModifiers, e.KeySymbol))
+        {
+            if (DataContext is not InteractiveTerminalViewModel altGrVm) return;
+            e.Handled = true;
+            _ = SendTextAndReportAsync(altGrVm, e.KeySymbol!);
+            return;
+        }
+
         if (e.Key != Key.V || !e.KeyModifiers.HasFlag(KeyModifiers.Control) || e.KeyModifiers.HasFlag(KeyModifiers.Alt))
             return;
         if (DataContext is not InteractiveTerminalViewModel vm) return;
@@ -120,6 +129,12 @@ public partial class InteractiveTerminalView : UserControl
             vm.ReportSendFailed();
     }
 
+    /// <summary>True for an AltGr keystroke (Windows reports it as Ctrl+Alt) whose
+    /// <paramref name="keySymbol"/> is already a single printable character, e.g. "@" or "\".</summary>
+    internal static bool IsAltGrText(KeyModifiers modifiers, string? keySymbol) =>
+        modifiers.HasFlag(KeyModifiers.Control) && modifiers.HasFlag(KeyModifiers.Alt)
+        && keySymbol is { Length: 1 } && !char.IsControl(keySymbol[0]);
+
     /// <summary>Joins dropped file paths into one insertable chunk: quoted when they contain a
     /// space, space-separated, with a trailing space so the user can keep typing.</summary>
     internal static string FormatDroppedPaths(IEnumerable<string?>? paths)