fix(app): keep dictation running when agent tab loses focus

Previously, dictation was cancelled the moment the user switched away
from the active agent tab, losing any in-progress recording. Drop the
auto-stop-on-blur behavior so users can start dictating, switch tabs,
and come back to finalize.

packages/app/src/components/message-input.tsx

@@ -1328,7 +1328,6 @@ export const MessageInput = forwardRef<MessageInputRef, MessageInputProps>(
       onError: handleDictationError,
       canStart: canStartDictation,
       canConfirm: canConfirmDictation,
-      autoStopWhenHidden: { isVisible: isPaneFocused },
       enableDuration: true,
     });