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/ViewModels/InteractiveTerminalViewModel.cs

@@ -1,6 +1,7 @@
 using System;
 using System.Threading.Tasks;
 using CommunityToolkit.Mvvm.ComponentModel;
+using ClaudeDo.Ui.Localization;
 using ClaudeDo.Ui.Services;
 using Iciclecreek.Terminal;
 
@@ -111,6 +112,15 @@ public sealed partial class InteractiveTerminalViewModel : ViewModelBase, IDispo
         }
     }
 
+    /// <summary>Raised when a user-initiated paste or drop couldn't reach the session (write seam
+    /// gone, no running process) — mirrors the island ViewModels' ErrorReported, forwarded by
+    /// <see cref="ClaudeDo.Ui.ViewModels.MissionControl.ConPtyPaneViewModel"/> into the footer error strip.</summary>
+    public event Action<string>? ErrorReported;
+
+    /// <summary>Called by the view after a failed <see cref="PasteAsync"/>/<see cref="SendTextAsync"/>
+    /// so the failure surfaces through <see cref="ErrorReported"/> instead of vanishing silently.</summary>
+    public void ReportSendFailed() => ErrorReported?.Invoke(Loc.T("missionControl.terminalSendFailed"));
+
     /// <summary>Raised when the process died non-zero *after* clearing <see cref="StartupGraceWindow"/> —
     /// i.e. a session that ran, then broke. That used to be a silent dead tile with no signal at all;
     /// the worker turns it into a usage-limit auto-restart for list-handler sessions
@@ -156,8 +166,9 @@ public sealed partial class InteractiveTerminalViewModel : ViewModelBase, IDispo
     public Task<bool> SendTextAsync(string text) => _session.SendTextAsync(text);
 
     /// <summary>Pastes the clipboard into the session (Ctrl+V) — see
-    /// <see cref="PtyTerminalSession.PasteAsync"/>.</summary>
-    public Task PasteAsync() => _session.PasteAsync();
+    /// <see cref="PtyTerminalSession.PasteAsync"/>. False when there is no running process to
+    /// paste into (or the write seam is gone).</summary>
+    public Task<bool> PasteAsync() => _session.PasteAsync();
 
     public void Kill() => _session.Kill();
 

src/ClaudeDo.Ui/ViewModels/MissionControl/ConPtyPaneViewModel.cs

@@ -89,14 +89,18 @@ public sealed partial class ConPtyPaneViewModel : ViewModelBase, IDisposable
     {
         terminal.PropertyChanged += OnTerminalPropertyChanged;
         terminal.ExitedAfterStartup += OnTerminalExitedAfterStartup;
+        terminal.ErrorReported += OnTerminalErrorReported;
     }
 
     private void Unsubscribe(InteractiveTerminalViewModel terminal)
     {
         terminal.PropertyChanged -= OnTerminalPropertyChanged;
         terminal.ExitedAfterStartup -= OnTerminalExitedAfterStartup;
+        terminal.ErrorReported -= OnTerminalErrorReported;
     }
 
+    private void OnTerminalErrorReported(string message) => ErrorReported?.Invoke(message);
+
     private void OnTerminalExitedAfterStartup(int exitCode)
     {
         if (TaskId is { } id) SessionDiedAfterStartup?.Invoke(id, exitCode);