Player: quick chat box, danmaku notifications, the player panel, smooth subtitle lift

- Quick chat (Enter in the full player, whatever plays): a box at the
  bottom centre in the control bar's place, compact and widening with
  the text, sharing its draft with the chat panel; Enter sends, Esc or an
  empty Enter closes, it closes by itself after 8 s without typing (the
  draft stays). Keys go to it; the Enter that opened it no longer reaches
  a focused button. Typing never shows the cursor or the controls: the
  frame wakes only on real mouse movement and holds the controls hidden
  while the box or its echo is up. Your sent line shows as an echo (or
  flies as your own danmaku line); your own chat toast is not repeated.
- Subtitle lift: always for the box, for the control bar as a setting
  (off); 4 eased-out sub-pos steps 42 ms apart instead of one per frame.
- Notifications: Toasts / Danmaku (off by default): chat and short notices
  fly over the full player, problems stay toasts; every knob of the look
  plus boldness, persisted, with a live preview strip in Settings.
- Player panel: ⚙ → Player settings docks a foldable glass panel at the
  right (tracks, subtitle size and lift, picture, volume, notifications,
  controls) in place of the card; Esc closes it.
- Danmaku preview: the mock dialogue follows the lift; the stand-in page
  has the chat box too.

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

apps/desktop/test/danmaku_test.dart

@@ -3,6 +3,8 @@ import 'dart:math' as math;
 import 'package:flutter/material.dart';
 import 'package:flutter_test/flutter_test.dart';
 import 'package:starsync/src/danmaku/danmaku.dart';
+import 'package:starsync/src/danmaku/danmaku_notices.dart';
+import 'package:starsync/src/session/notifier.dart' show NoticeCategory, ToastItem;
 import 'package:starsync/src/shell/avatar.dart' show AvatarInfo;
 
 // Danmaku lanes: free lanes only, no two lines in a lane ever touch, the
@@ -173,4 +175,87 @@ void main() {
     expect(c.waiting.value, 0);
     await tester.pumpWidget(const SizedBox());
   });
+
+
+  group('DanmakuStyle as a setting', () {
+    test('round-trips through its map', () {
+      const s = DanmakuStyle(
+          crossSecs: 6, maxOnScreen: 5, bandTop: 0.2, bandBottom: 0.5, opacity: 0.7, size: 1.3, weight: 800,
+          outline: 2, highlightOwn: false, avatars: false);
+      expect(DanmakuStyle.fromJson(s.toJson()), s);
+    });
+
+    test('junk and out-of-range values: defaults and the nearest ends', () {
+      expect(DanmakuStyle.fromJson(const {}), const DanmakuStyle());
+      final s = DanmakuStyle.fromJson(const {
+        'crossSecs': 99,
+        'maxOnScreen': 0,
+        'opacity': 'x',
+        'weight': 1234,
+        'bandTop': 0.6,
+        'bandBottom': 0.61,
+        'avatars': 1,
+      });
+      expect(s.crossSecs, 16);
+      expect(s.maxOnScreen, 1);
+      expect(s.opacity, const DanmakuStyle().opacity);
+      expect(s.weight, 900);
+      expect((s.bandTop, s.bandBottom), (0.10, 0.45), reason: 'a band too thin takes the default');
+      expect(s.avatars, isTrue);
+    });
+
+    test('boldness: the text at its weight, the name a step bolder', () {
+      expect(const DanmakuStyle(weight: 400).fontWeight, FontWeight.w400);
+      expect(const DanmakuStyle(weight: 400).nameWeight, FontWeight.w500);
+      expect(const DanmakuStyle(weight: 900).nameWeight, FontWeight.w900);
+    });
+  });
+
+  group('notifications as danmaku', () {
+    ToastItem toast(String text,
+            {String? actor, NoticeCategory category = NoticeCategory.app, bool chat = false, bool own = false}) =>
+        ToastItem(id: 1, text: text, at: DateTime(2026), actor: actor, chat: chat, own: own, category: category);
+
+    test('chat and short notices fly; problems, nudges and the app stay toasts', () {
+      expect(fliesAsDanmaku(toast('Bob: hi', actor: 'Bob', chat: true, category: NoticeCategory.chat)), isTrue);
+      expect(fliesAsDanmaku(toast('Bob joined', actor: 'Bob', category: NoticeCategory.people)), isTrue);
+      expect(fliesAsDanmaku(toast('Starting now', category: NoticeCategory.start)), isTrue);
+      expect(fliesAsDanmaku(toast('Bob added X to Up next', actor: 'Bob', category: NoticeCategory.upNext)), isTrue);
+      expect(fliesAsDanmaku(toast('Skipped X: gone', category: NoticeCategory.upNext)), isFalse);
+      expect(fliesAsDanmaku(toast("Bob can't play this", actor: 'Bob', category: NoticeCategory.problem)), isFalse);
+      expect(fliesAsDanmaku(toast('Bob nudged you', actor: 'Bob', category: NoticeCategory.nudge)), isFalse);
+      expect(fliesAsDanmaku(toast('Link copied')), isFalse);
+      expect(fliesAsDanmaku(toast('The server restarted', category: NoticeCategory.self)), isFalse);
+    });
+
+    test('lines: the sender before the message, own chat framed', () {
+      final chat = danmakuForToast(toast('Me: hello', actor: 'Me', chat: true, own: true, category: NoticeCategory.chat))!;
+      expect((chat.kind, chat.sender, chat.text, chat.own), (DanmakuKind.chat, 'Me', 'hello', true));
+      final left = danmakuForToast(toast('Bob lost connection', actor: 'Bob', category: NoticeCategory.people))!;
+      expect((left.kind, left.text), (DanmakuKind.leave, 'lost connection'));
+      final start = danmakuForToast(toast('Starting now: Frieren', category: NoticeCategory.start))!;
+      expect((start.kind, start.sender), (DanmakuKind.starting, null));
+      expect(danmakuForToast(toast('Copied')), isNull);
+    });
+  });
+
+  testWidgets('an idle layer asks for no frames', (tester) async {
+    final c = DanmakuController();
+    addTearDown(c.dispose);
+    await tester.pumpWidget(Directionality(
+      textDirection: TextDirection.ltr,
+      child: SizedBox(width: 800, height: 450, child: DanmakuLayer(controller: c, accent: Colors.purple)),
+    ));
+    await tester.pump(const Duration(milliseconds: 16));
+    expect(tester.binding.hasScheduledFrame, isFalse);
+    c.add(const DanmakuItem(kind: DanmakuKind.chat, sender: 'Bob', text: 'hi'));
+    await tester.pump(const Duration(milliseconds: 16));
+    expect(c.onScreen.value, 1);
+    expect(tester.binding.hasScheduledFrame, isTrue);
+    await tester.pump(const Duration(seconds: 9));
+    await tester.pump(const Duration(milliseconds: 16));
+    expect(c.onScreen.value, 0);
+    expect(tester.binding.hasScheduledFrame, isFalse);
+    await tester.pumpWidget(const SizedBox());
+  });
 }