Return the keyboard on Remote shortcuts and announce focus changes

During remote focus a Remote shortcut now ends capture, like F11,
instead of running its command, which would race with the focus change.
The reader announces when the keyboard starts and stops controlling the
remote computer, and the consent wording names the F11 escape.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

internal/app/tentacle_remote_capture.go

@@ -105,8 +105,10 @@ func (runtime *tentacleRuntime) start_remote_capture(ctx context.Context, sessio
 				id, stream, err := capture.BeginRemoteCapture(request.Context, prefix)
 				if err != nil {
 					_ = session.PublishRemoteFocus(request.Lease, tentaclewire.RemoteFocusLocal, "unavailable")
+					runtime.report("Remote keyboard control is unavailable.")
 					continue
 				}
+				runtime.report("Keyboard controls the remote computer. Press F11 to return.")
 				active, lease, events, leaseDone = id, request.Lease, stream, request.Context.Done()
 				if session.PublishRemoteFocus(lease, tentaclewire.RemoteFocusRemote, "requested") != nil {
 					end()
@@ -118,6 +120,7 @@ func (runtime *tentacleRuntime) start_remote_capture(ctx context.Context, sessio
 				}
 				if event.Ended != "" {
 					_ = session.PublishRemoteFocus(lease, tentaclewire.RemoteFocusLocal, event.Ended)
+					runtime.report("Keyboard returned to this computer.")
 					continue
 				}
 				key := tentaclewire.RemoteCapturedKey{Code: int(event.Key.Code), Name: event.Key.Name, Pressed: event.Key.Pressed, Repeat: event.Key.Repeat}