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/test/shell_test.dart

@@ -166,13 +166,13 @@ void main() {
         expect(find.descendant(of: card, matching: find.text(m.name)), findsOneWidget);
       }
       expect(find.descendant(of: card, matching: find.text('reconnecting…')), findsOneWidget);
-      // The kick menu asks before kicking.
+      // Someone else: nudge or sit them out (no kicking).
       await tester.tap(find.descendant(of: find.byKey(const ValueKey('member-b')), matching: find.byTooltip('More')));
       await tester.pumpAndSettle();
-      await tester.tap(find.text('Kick'));
-      await tester.pumpAndSettle();
-      expect(find.text('Remove Bob?'), findsOneWidget);
-      await tester.tap(find.text('Cancel'));
+      expect(find.text('Nudge'), findsOneWidget);
+      expect(find.text('Sit out'), findsOneWidget);
+      expect(find.text('Kick'), findsNothing);
+      await tester.sendKeyEvent(LogicalKeyboardKey.escape);
       await tester.pumpAndSettle();
       await tester.tapAt(const Offset(40, 700));
       await tester.pumpAndSettle();