fix(home): 频道切换用封面过渡

lib/pages/player/player_view.dart

@@ -378,6 +378,7 @@ class _PlayerPageState extends State<PlayerPage>
         PlayerVideoSurface(
           controller: videoPort?.controller,
           videoUrl: videoPort?.controller.dataSource ?? episode.videoUrl,
+          posterUrl: drama.posterUrl,
           theater: theater,
           onTap: () =>
               logic.session.setUserWantsPlay(!logic.session.userWantsPlay),
@@ -427,7 +428,7 @@ class _PlayerPageState extends State<PlayerPage>
               ),
             ),
           ),
-        if (selected && logic.session.loading)
+        if (selected && logic.session.loading && !widget.homeMode)
           const Center(
             child: CircularProgressIndicator(
               key: Key('player-session-loading'),

lib/pages/player/widgets/player_video_surface.dart

@@ -4,22 +4,26 @@ import 'package:flutter/foundation.dart';
 import 'package:flutter/material.dart';
 import 'package:video_player/video_player.dart';
 
+import '../../../core/widgets/remote_image.dart';
+
 const Duration _videoFadeDuration = Duration(milliseconds: 200);
 const double _errorHorizontal = 32;
 const int _errorMaxLines = 3;
 
-/// 黑色底层与视频层共用同一控制器，视频首帧就绪后再淡入。
+/// 封面或黑色底层与视频层共用同一控制器，视频首帧就绪后再淡入。
 class PlayerVideoSurface extends StatefulWidget {
   const PlayerVideoSurface({
     super.key,
     required this.controller,
     required this.videoUrl,
+    this.posterUrl = '',
     required this.theater,
     required this.onTap,
   });
 
   final VideoPlayerController? controller;
   final String videoUrl;
+  final String posterUrl;
   final bool theater;
   final VoidCallback onTap;
 
@@ -53,10 +57,17 @@ class _PlayerVideoSurfaceState extends State<PlayerVideoSurface> {
     return Stack(
       fit: StackFit.expand,
       children: [
-        const ColoredBox(
-          key: Key('player-fallback-background'),
-          color: Colors.black,
-        ),
+        if (widget.posterUrl.isEmpty)
+          const ColoredBox(
+            key: Key('player-fallback-background'),
+            color: Colors.black,
+          )
+        else
+          RemoteImage(
+            widget.posterUrl,
+            key: const Key('player-video-poster'),
+            fit: BoxFit.cover,
+          ),
         AnimatedOpacity(
           key: const Key('player-video-opacity'),
           opacity: reveal ? 1 : 0,