Revert "merge: 合并 K95.2 首切频道封面过渡"

This reverts commit a2a491d056, reversing
changes made to 838ca2ce2a.

test/player/player_fullscreen_test.dart

@@ -131,12 +131,18 @@ void main() {
     expect(player.playing, isTrue);
   });
 
-  testWidgets('should_show_poster_before_video_first_frame', (tester) async {
+  testWidgets('should_keep_video_surface_background_black', (tester) async {
     await _pumpApp(tester);
     await _openSeriesPlayer(tester);
 
-    expect(find.byKey(const Key('player-video-poster')), findsOneWidget);
-    expect(find.byKey(const Key('player-fallback-background')), findsNothing);
+    expect(
+      tester
+          .widget<ColoredBox>(
+            find.byKey(const Key('player-fallback-background')),
+          )
+          .color,
+      Colors.black,
+    );
     expect(find.byKey(const Key('player-fallback-cover')), findsNothing);
     expect(find.byKey(const Key('player-fallback-scrim')), findsNothing);
   });
@@ -465,8 +471,9 @@ void main() {
       find.byKey(const Key('player-interaction-rail')),
     );
     expect(find.byKey(const Key('player-background')), findsNothing);
-    expect(find.byKey(const Key('player-video-poster')), findsOneWidget);
-    expect(find.byKey(const Key('player-fallback-background')), findsNothing);
+    final fallback = find.byKey(const Key('player-fallback-background'));
+    expect(fallback, findsOneWidget);
+    expect(tester.widget<ColoredBox>(fallback).color, Colors.black);
     expect(find.byKey(const Key('player-fallback-cover')), findsNothing);
     expect(find.byKey(const Key('player-fallback-scrim')), findsNothing);
     expect(

test/player/player_video_surface_test.dart

@@ -7,24 +7,6 @@ import 'package:video_player/video_player.dart';
 import 'package:fruitshorts/pages/player/widgets/player_video_surface.dart';
 
 void main() {
-  testWidgets('should_show_poster_when_controller_is_missing', (tester) async {
-    await _pumpBareSurface(tester, posterUrl: '/files/poster.png');
-
-    expect(find.byKey(const Key('player-video-poster')), findsOneWidget);
-    expect(find.byKey(const Key('player-fallback-background')), findsNothing);
-    expect(_opacity(tester), 0);
-  });
-
-  testWidgets('should_keep_black_fallback_when_poster_is_empty', (
-    tester,
-  ) async {
-    await _pumpBareSurface(tester);
-
-    expect(find.byKey(const Key('player-video-poster')), findsNothing);
-    expect(_fallbackColor(tester), Colors.black);
-    expect(_opacity(tester), 0);
-  });
-
   testWidgets('should_keep_fallback_visible_before_video_is_ready', (
     tester,
   ) async {
@@ -114,25 +96,6 @@ Future<VideoPlayerController> _pumpSurface(
   return controller;
 }
 
-Future<void> _pumpBareSurface(
-  WidgetTester tester, {
-  String posterUrl = '',
-}) async {
-  await tester.pumpWidget(
-    MaterialApp(
-      home: Scaffold(
-        body: PlayerVideoSurface(
-          controller: null,
-          videoUrl: '',
-          posterUrl: posterUrl,
-          theater: false,
-          onTap: () {},
-        ),
-      ),
-    ),
-  );
-}
-
 Color _fallbackColor(WidgetTester tester) {
   return tester
       .widget<ColoredBox>(find.byKey(const Key('player-fallback-background')))