fix(ui): report failed paste/drop in the interactive terminal

PasteAsync silently swallowed every exception and returned void, so a
package update renaming Iciclecreek's private write seam would break
Ctrl+V/drop with zero user-visible signal. PasteAsync/SendTextAsync now
return bool (mirroring SendLineAsync), and the view checks the result,
routing a failure through InteractiveTerminalViewModel.ErrorReported ->
ConPtyPaneViewModel.ErrorReported -> the existing footer error strip.

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

@@ -43,7 +43,13 @@ public partial class InteractiveTerminalView : UserControl
         if (DataContext is not InteractiveTerminalViewModel vm) return;
 
         e.Handled = true;
-        _ = vm.PasteAsync();
+        _ = PasteAndReportAsync(vm);
+    }
+
+    private static async System.Threading.Tasks.Task PasteAndReportAsync(InteractiveTerminalViewModel vm)
+    {
+        if (!await vm.PasteAsync())
+            vm.ReportSendFailed();
     }
 
     private static bool IsFilesDrop(DragEventArgs e) => e.DataTransfer?.Contains(DataFormat.File) == true;
@@ -62,7 +68,13 @@ public partial class InteractiveTerminalView : UserControl
         e.Handled = true;
 
         var text = FormatDroppedPaths(e.DataTransfer!.TryGetFiles()?.Select(i => i.TryGetLocalPath()));
-        if (text.Length > 0) _ = vm.SendTextAsync(text);
+        if (text.Length > 0) _ = SendTextAndReportAsync(vm, text);
+    }
+
+    private static async System.Threading.Tasks.Task SendTextAndReportAsync(InteractiveTerminalViewModel vm, string text)
+    {
+        if (!await vm.SendTextAsync(text))
+            vm.ReportSendFailed();
     }
 
     /// <summary>Joins dropped file paths into one insertable chunk: quoted when they contain a