Protocol 11: sit out replaces kicking; nudge

Anyone can sit anyone out (host included); only you bring yourself back.
Out members stay in chat and the party, never block or count, and load no
media; a card with the live position and Join back (Space) replaces the
video. The mini player's x sits you out; optionally idle does too. Nudge:
the server forwards it to the target only (3/s, 20/min per sender); the
target hears the nudge sound, gets a toast and a taskbar attention
request. Kick, its messages, errors and dialog are gone.

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

apps/desktop/lib/src/widgets/dialogs.dart

@@ -1,22 +0,0 @@
-import 'package:flutter/material.dart';
-
-Future<bool?> showKickConfirmDialog(
-    BuildContext context, String memberName) {
-  return showDialog<bool>(
-    context: context,
-    builder: (context) => AlertDialog(
-      title: Text('Remove $memberName?'),
-      content: const Text('They can come straight back in.'),
-      actions: [
-        TextButton(
-          onPressed: () => Navigator.pop(context, false),
-          child: const Text('Cancel'),
-        ),
-        TextButton(
-          onPressed: () => Navigator.pop(context, true),
-          child: const Text('Remove'),
-        ),
-      ],
-    ),
-  );
-}