Desktop: video freeze recovery, session fixes, Home redesign

- Player + VideoController per session; Reload video (Ctrl+R) and a
  frozen-picture watchdog that reloads automatically.
- Shortcuts no longer fire while typing; empty swap disabled;
  hwdec setting/env actually applied.
- Idle unready measured from real inactivity; cancellable reconnects
  and setup; ready restored from server state; kicked/failed host
  stops its server; graceful leave on window close; no URLs with
  keys in display names.
- Welcome + connect screens replaced by one Home screen with Join and
  Host cards, recent servers, Settings, Integrations and About.

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

apps/desktop/test/video_reload_e2e_test.dart

@@ -0,0 +1,74 @@
+import 'dart:async';
+
+import 'package:flutter_test/flutter_test.dart';
+import 'package:media_kit/media_kit.dart';
+import 'package:sync_relay_core/core.dart';
+import 'package:sync_relay_server/server.dart';
+import 'package:watch_together/src/session/session_coordinator.dart';
+import 'package:watch_together/src/sync/room_diff.dart';
+
+const _mediaPath = '/home/foxyz/Videos/chiyo.mp4';
+
+Future<void> _poll(
+  FutureOr<bool> Function() cond,
+  String what, {
+  Duration timeout = const Duration(seconds: 30),
+}) async {
+  final deadline = DateTime.now().add(timeout);
+  while (DateTime.now().isBefore(deadline)) {
+    if (await cond()) return;
+    await Future.delayed(const Duration(milliseconds: 200));
+  }
+  fail('timed out waiting for $what');
+}
+
+void main() {
+  test(
+    'reload video: new player, same media, resynced, ready untouched; '
+    'leave disposes the player',
+    timeout: const Timeout(Duration(minutes: 2)),
+    () async {
+      MediaKit.ensureInitialized();
+      final server = RoomServer(const AppConfig(
+          port: 0, secret: 'reload', name: 'reload', mediaPath: _mediaPath));
+      await server.start();
+      final c = SessionCoordinator();
+      try {
+        await c.connect(ConnectParams(
+            host: '127.0.0.1',
+            port: server.boundPort,
+            secret: 'reload',
+            name: 'solo'));
+        await c.playback.player.setVolume(0);
+        await _poll(() => c.room.peek() != null, 'room state');
+        c.toggleReady();
+        await _poll(
+            () => c.playback.player.state.playing && c.playback.positionSecs > 2,
+            'solo playback past 2 s');
+
+        final old = c.playback.player;
+        final gen = c.playback.generation.peek();
+        await c.reloadVideo();
+        expect(identical(c.playback.player, old), isFalse);
+        expect(c.playback.generation.peek(), gen + 1);
+        expect(c.selfMember.peek()?.ready, isTrue);
+
+        await _poll(() {
+          final r = c.room.peek();
+          if (r == null || !c.playback.player.state.playing) return false;
+          final want = roomPositionAt(r, DateTime.now().toUtc());
+          return (c.playback.positionSecs - want).abs() < 1.5 &&
+              c.playback.positionSecs > 2;
+        }, 'reloaded player playing at the synced position');
+        expect(c.selfMember.peek()?.ready, isTrue);
+        expect(c.room.peek()?.transport, 'playing');
+
+        await c.leave();
+        expect(c.playback.alive.peek(), isFalse);
+      } finally {
+        await c.dispose();
+        await server.stop();
+      }
+    },
+  );
+}