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/lib/src/screens/home/ui.dart

@@ -0,0 +1,123 @@
+import 'package:flutter/material.dart';
+
+/// Product name (working title). Change it here only.
+const appName = 'Watch Together';
+
+const repoUrl = 'https://git.senkochan.moe/Foxyz/sync_replay_project';
+
+const kRadius = 12.0;
+const kGap = 16.0;
+const kPagePadding = EdgeInsets.fromLTRB(28, 20, 28, 28);
+
+/// Rounded panel used by every Home/Settings section.
+class Panel extends StatelessWidget {
+  final Widget child;
+  final EdgeInsetsGeometry padding;
+  final bool enabled;
+  const Panel(
+      {super.key,
+      required this.child,
+      this.padding = const EdgeInsets.all(20),
+      this.enabled = true});
+
+  @override
+  Widget build(BuildContext context) {
+    final scheme = Theme.of(context).colorScheme;
+    // Material (not a DecoratedBox) so ink from tiles/chips inside shows.
+    final panel = Material(
+      color: scheme.surfaceContainer,
+      shape: RoundedRectangleBorder(
+        borderRadius: BorderRadius.circular(kRadius),
+        side: BorderSide(color: scheme.outlineVariant.withValues(alpha: 0.5)),
+      ),
+      clipBehavior: Clip.antiAlias,
+      child: Padding(padding: padding, child: child),
+    );
+    if (enabled) return panel;
+    return Opacity(opacity: 0.5, child: IgnorePointer(child: panel));
+  }
+}
+
+/// Page heading + optional subtitle, same spacing everywhere.
+class PageTitle extends StatelessWidget {
+  final String title;
+  final String? subtitle;
+  const PageTitle(this.title, {super.key, this.subtitle});
+
+  @override
+  Widget build(BuildContext context) {
+    final t = Theme.of(context).textTheme;
+    return Padding(
+      padding: const EdgeInsets.only(bottom: kGap),
+      child: Column(
+        crossAxisAlignment: CrossAxisAlignment.start,
+        children: [
+          Text(title, style: t.headlineSmall),
+          if (subtitle != null)
+            Padding(
+              padding: const EdgeInsets.only(top: 4),
+              child: Text(subtitle!,
+                  style: t.bodyMedium?.copyWith(color: Colors.grey)),
+            ),
+        ],
+      ),
+    );
+  }
+}
+
+/// Small grey heading inside a panel.
+class SectionLabel extends StatelessWidget {
+  final String text;
+  final Widget? trailing;
+  const SectionLabel(this.text, {super.key, this.trailing});
+
+  @override
+  Widget build(BuildContext context) {
+    return Padding(
+      padding: const EdgeInsets.only(bottom: 12),
+      child: Row(
+        children: [
+          Expanded(
+            child: Text(text, style: Theme.of(context).textTheme.titleMedium),
+          ),
+          ?trailing,
+        ],
+      ),
+    );
+  }
+}
+
+/// Text field style shared by the connect cards.
+InputDecoration fieldDecoration(String label, {String? hint, Widget? suffix}) =>
+    InputDecoration(
+      labelText: label,
+      hintText: hint,
+      isDense: true,
+      suffixIcon: suffix,
+      border: OutlineInputBorder(borderRadius: BorderRadius.circular(8)),
+    );
+
+/// Single-item scrollable page body, width-capped so it doesn't sprawl
+/// on wide windows.
+class PageScroll extends StatelessWidget {
+  final List<Widget> children;
+  final double maxWidth;
+  const PageScroll({super.key, required this.children, this.maxWidth = 920});
+
+  @override
+  Widget build(BuildContext context) {
+    return SingleChildScrollView(
+      padding: kPagePadding,
+      child: Align(
+        alignment: Alignment.topLeft,
+        child: ConstrainedBox(
+          constraints: BoxConstraints(maxWidth: maxWidth),
+          child: Column(
+            crossAxisAlignment: CrossAxisAlignment.stretch,
+            children: children,
+          ),
+        ),
+      ),
+    );
+  }
+}