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.

tests/ClaudeDo.Ui.Tests/Services/PtyTerminalSessionTests.cs

@@ -35,4 +35,14 @@ public class PtyTerminalSessionTests
 
         Assert.Equal(0, gate.CurrentCount); // acquired
     }
+
+    // Fix: PasteAsync used to be void and swallow every failure. Not-started is the cheap case to
+    // cover without a real TerminalControl/ConPTY spawn.
+    [Fact]
+    public async Task PasteAsync_ReturnsFalse_WhenNotStarted()
+    {
+        using var session = new PtyTerminalSession();
+
+        Assert.False(await session.PasteAsync());
+    }
 }

tests/ClaudeDo.Ui.Tests/ViewModels/MissionControl/ConPtyPaneViewModelTests.cs

@@ -219,6 +219,35 @@ public class ConPtyPaneViewModelTests
         Assert.True(raised);
     }
 
+    // ── Terminal.ErrorReported forwarding (fix: a failed paste/drop had no path to the footer
+    //    error strip) ────────────────────────────────────────────────────────────────────────────
+
+    [Fact]
+    public void TerminalErrorReported_Forwards_ToPaneErrorReported()
+    {
+        using var pane = NewTaskPane(NeverCompletes);
+        string? error = null;
+        pane.ErrorReported += msg => error = msg;
+
+        pane.Terminal.ReportSendFailed();
+
+        Assert.NotNull(error);
+    }
+
+    [Fact]
+    public void TerminalErrorReported_StillWiredAfterRetry()
+    {
+        using var pane = NewTaskPane(() => Failing());
+        pane.Start();
+        pane.RetryCommand.Execute(null);
+        string? error = null;
+        pane.ErrorReported += msg => error = msg;
+
+        pane.Terminal.ReportSendFailed();
+
+        Assert.NotNull(error);
+    }
+
     private static void SetRunning(ConPtyPaneViewModel pane) => pane.Terminal.IsRunning = true;
 
     // Drives the terminal past its startup grace window, then kills it: IsRunning stamps the launch

tests/ClaudeDo.Ui.Tests/ViewModels/MissionControl/InteractiveTerminalViewModelTests.cs

@@ -124,4 +124,35 @@ public class InteractiveTerminalViewModelTests
         terminal.IsRunning = true; // records LaunchedAt via the first clock call
         return terminal;
     }
+
+    // ── Paste/drop failure reporting (fix: PasteAsync used to swallow every exception and return
+    //    void, so a failed Ctrl+V or file drop gave the user no signal at all) ────────────────────
+
+    [Fact]
+    public async Task PasteAsync_ReturnsFalse_WhenSessionNotRunning()
+    {
+        using var terminal = new InteractiveTerminalViewModel();
+
+        Assert.False(await terminal.PasteAsync());
+    }
+
+    [Fact]
+    public async Task SendTextAsync_ReturnsFalse_WhenSessionNotRunning()
+    {
+        using var terminal = new InteractiveTerminalViewModel();
+
+        Assert.False(await terminal.SendTextAsync("dropped/path"));
+    }
+
+    [Fact]
+    public void ReportSendFailed_RaisesErrorReported()
+    {
+        using var terminal = new InteractiveTerminalViewModel();
+        string? error = null;
+        terminal.ErrorReported += msg => error = msg;
+
+        terminal.ReportSendFailed();
+
+        Assert.NotNull(error);
+    }
 }