Player overlay as one piece, Up next always warm and on every source, Jellyfin never unmarks a watched episode

- Overlay: one layout for both designs (top bar with Up next as one of
  its buttons; one action band above the controls for the status pill,
  skips, next episode and end cards), one glass recipe (AppGlass) and
  one pill (FloatingPill); hovering any of them, or the open queue,
  holds the controls up.
- Up next: the first item (or the first continuation episode) is kept
  resolved on the app that puts it up, refreshed before it expires;
  Schedule and drop/paste can queue too.
- Jellyfin: WatchSession (core) counts real watched coverage; an
  episode is watched at 80 % or at its ending after half; a played one
  is re-marked after Playing (10.11 unmarks on open) and never gets a
  position; a peek leaves the old resume point; part-way resume points
  stay under 85 %.

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

apps/desktop/lib/src/controls/controls_probe.dart

@@ -2,16 +2,92 @@ import 'dart:async';
 
 import 'package:flutter/material.dart';
 
+/// What keeps the player's controls up besides the mouse on them: the
+/// mouse on a floating element over the picture (a pill, a card, the
+/// status pill: [ControlsHoldRegion]) or an open popover. While anything
+/// holds, the controls stay up; on release they hide on their usual
+/// countdown. Both designs follow it ([ControlsHoverProbe] with
+/// media_kit's controls, `UoscControls`).
+class ControlsHold extends ChangeNotifier {
+  final _by = <Object>{};
+  bool _told = false;
+  bool _queued = false;
+  bool _disposed = false;
+
+  bool get held => _told;
+
+  /// [who] holds ([on]) or lets go. Listeners hear it in a microtask, never
+  /// during a build or a dispose.
+  void set(Object who, bool on) {
+    if (on ? !_by.add(who) : !_by.remove(who)) return;
+    if (_queued) return;
+    _queued = true;
+    scheduleMicrotask(() {
+      _queued = false;
+      if (_disposed) return;
+      final now = _by.isNotEmpty;
+      if (now == _told) return;
+      _told = now;
+      notifyListeners();
+    });
+  }
+
+  @override
+  void dispose() {
+    _disposed = true;
+    super.dispose();
+  }
+}
+
+/// The mouse on [child] counts as the mouse on the controls: it holds
+/// [hold] while it is there.
+class ControlsHoldRegion extends StatefulWidget {
+  final ControlsHold? hold;
+  final Widget child;
+  const ControlsHoldRegion({super.key, required this.hold, required this.child});
+
+  @override
+  State<ControlsHoldRegion> createState() => _ControlsHoldRegionState();
+}
+
+class _ControlsHoldRegionState extends State<ControlsHoldRegion> {
+  @override
+  void didUpdateWidget(ControlsHoldRegion oldWidget) {
+    super.didUpdateWidget(oldWidget);
+    if (oldWidget.hold != widget.hold) oldWidget.hold?.set(this, false);
+  }
+
+  @override
+  void dispose() {
+    widget.hold?.set(this, false);
+    super.dispose();
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    final hold = widget.hold;
+    if (hold == null) return widget.child;
+    return MouseRegion(
+      onEnter: (_) => hold.set(this, true),
+      onExit: (_) => hold.set(this, false),
+      child: widget.child,
+    );
+  }
+}
+
 /// Follows whether media_kit's desktop controls around [child] are up,
 /// by the same rule they use: up on mount and on any mouse movement,
 /// down [hideAfter] later or when the mouse leaves. media_kit does not
 /// expose its visibility; this lets the player draw a progress line while
-/// they are down. Never takes input.
+/// they are down. With [hold] held it keeps them (and itself) up. Never
+/// takes input.
 class ControlsHoverProbe extends StatefulWidget {
   final ValueNotifier<bool> shown;
   final Duration hideAfter;
+  final ControlsHold? hold;
   final Widget child;
-  const ControlsHoverProbe({super.key, required this.shown, required this.hideAfter, required this.child});
+  const ControlsHoverProbe(
+      {super.key, required this.shown, required this.hideAfter, this.hold, required this.child});
 
   @override
   State<ControlsHoverProbe> createState() => _ControlsHoverProbeState();
@@ -19,22 +95,67 @@ class ControlsHoverProbe extends StatefulWidget {
 
 class _ControlsHoverProbeState extends State<ControlsHoverProbe> {
   Timer? _timer;
+  // While held: media_kit's own countdown is restarted before it ends.
+  Timer? _keep;
+
+  bool get _held => widget.hold?.held ?? false;
 
   @override
   void initState() {
     super.initState();
+    widget.hold?.addListener(_holdChanged);
     // Not during this build: the line listening to [shown] may be built.
     WidgetsBinding.instance.addPostFrameCallback((_) {
       if (mounted) _wake();
     });
   }
 
+  @override
+  void didUpdateWidget(ControlsHoverProbe oldWidget) {
+    super.didUpdateWidget(oldWidget);
+    if (oldWidget.hold != widget.hold) {
+      oldWidget.hold?.removeListener(_holdChanged);
+      widget.hold?.addListener(_holdChanged);
+      _holdChanged();
+    }
+  }
+
   @override
   void dispose() {
+    widget.hold?.removeListener(_holdChanged);
     _timer?.cancel();
+    _keep?.cancel();
     super.dispose();
   }
 
+  void _holdChanged() {
+    if (!mounted) return;
+    _keep?.cancel();
+    _keep = null;
+    if (_held) {
+      _keep = Timer.periodic(widget.hideAfter * 0.5, (_) => _pokeControls());
+    }
+    _pokeControls();
+    _wake();
+  }
+
+  /// media_kit's controls state is private: a guarded dynamic call to its
+  /// hover handler, as a mouse movement on it would make.
+  void _pokeControls() {
+    if (!mounted) return;
+    void visit(Element e) {
+      if (e is StatefulElement && e.state.runtimeType.toString() == '_MaterialDesktopVideoControlsState') {
+        try {
+          (e.state as dynamic).onHover();
+        } catch (_) {}
+        return;
+      }
+      e.visitChildElements(visit);
+    }
+
+    context.visitChildElements(visit);
+  }
+
   void _wake() {
     widget.shown.value = true;
     _timer?.cancel();
@@ -43,7 +164,8 @@ class _ControlsHoverProbeState extends State<ControlsHoverProbe> {
 
   void _hide() {
     _timer?.cancel();
-    if (mounted) widget.shown.value = false;
+    if (!mounted || _held) return;
+    widget.shown.value = false;
   }
 
   @override
@@ -52,7 +174,9 @@ class _ControlsHoverProbeState extends State<ControlsHoverProbe> {
         hitTestBehavior: HitTestBehavior.translucent,
         onEnter: (_) => _wake(),
         onHover: (_) => _wake(),
-        onExit: (_) => _hide(),
+        // Held (the mouse went onto a pill or the popover): media_kit's
+        // controls just hid on their own exit; bring them straight back.
+        onExit: (_) => _held ? _pokeControls() : _hide(),
         child: widget.child,
       );
 }