style(player): 播放页与首页浮层的控件样式统一

播放页顶部按钮与选集条去掉底色、进度条不再画滑块圆点并压到最底部；
剧名与简介收在互动栏左侧，清屏后只留右下角退出按钮。
首页观看条与进度条共用 20pt 页边距，进度槽底色与播放页一致。

lib/pages/player/widgets/exit_clear_screen_button.dart

@@ -4,6 +4,10 @@ import 'package:flutter/material.dart';
 
 import '../../../core/theme/app_colors.dart';
 
+const List<Shadow> _iconShadows = [
+  Shadow(color: AppColors.shadow, blurRadius: 6, offset: Offset(0, 1)),
+];
+
 /// Shared floating action used to leave clear-screen mode.
 class ExitClearScreenButton extends StatelessWidget {
   const ExitClearScreenButton({
@@ -25,11 +29,15 @@ class ExitClearScreenButton extends StatelessWidget {
         onPressed: onPressed,
         padding: EdgeInsets.zero,
         style: IconButton.styleFrom(
-          backgroundColor: AppColors.controlScrim,
+          backgroundColor: AppColors.transparent,
           foregroundColor: AppColors.onPrimary,
           shape: const CircleBorder(),
         ),
-        icon: const Icon(Icons.fullscreen_exit_rounded, size: 18),
+        icon: const Icon(
+          Icons.fullscreen_exit_rounded,
+          size: 22,
+          shadows: _iconShadows,
+        ),
       ),
     );
   }