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/session/idle.dart

@@ -0,0 +1,43 @@
+enum IdleEvent { none, warn, unready }
+
+/// Idle auto-unready clock. Idle time counts from the later of the user's
+/// last input and the last moment playback was running: watching is
+/// activity, so a long watch followed by a pause starts a fresh 10 min.
+/// The unready also always trails its warning by the full grace period.
+class IdleTracker {
+  static const warnAfter = Duration(minutes: 8);
+  static const unreadyAfter = Duration(minutes: 10);
+
+  DateTime _lastActive;
+  DateTime? _warnedAt;
+
+  IdleTracker(DateTime now) : _lastActive = now;
+
+  void activity(DateTime now) {
+    _lastActive = now;
+    _warnedAt = null;
+  }
+
+  /// Called once per tick. Warn and unready only matter while self is
+  /// ready; while the room plays the ready flag gates nothing.
+  IdleEvent tick(DateTime now, {required bool playing, required bool selfReady}) {
+    if (playing) {
+      activity(now);
+      return IdleEvent.none;
+    }
+    if (!selfReady) return IdleEvent.none;
+    final warnedAt = _warnedAt;
+    if (warnedAt != null) {
+      if (now.difference(warnedAt) >= unreadyAfter - warnAfter) {
+        activity(now);
+        return IdleEvent.unready;
+      }
+      return IdleEvent.none;
+    }
+    if (now.difference(_lastActive) >= warnAfter) {
+      _warnedAt = now;
+      return IdleEvent.warn;
+    }
+    return IdleEvent.none;
+  }
+}