fix(player): 统一暂停按钮并自动隐藏控制层

lib/pages/player/widgets/home_feed_overlay.dart

@@ -55,7 +55,7 @@ class HomeFeedOverlay extends StatelessWidget {
             child: Align(
               alignment: Alignment.centerRight,
               child: Padding(
-                padding: const EdgeInsets.fromLTRB(0, 0, 10, 12),
+                padding: const EdgeInsets.fromLTRB(0, 0, 12, 16),
                 child: _rail(),
               ),
             ),

lib/pages/player/widgets/player_center_toggle.dart

@@ -0,0 +1,41 @@
+// Author: fruit.com.cn
+
+import 'package:flutter/material.dart';
+
+import '../../../core/theme/app_colors.dart';
+
+/// Shared play/pause control used by the home feed and full-screen player.
+class PlayerCenterToggle extends StatelessWidget {
+  const PlayerCenterToggle({
+    super.key,
+    required this.playing,
+    required this.onTap,
+  });
+
+  final bool playing;
+  final VoidCallback onTap;
+
+  @override
+  Widget build(BuildContext context) {
+    return Semantics(
+      button: true,
+      label: playing ? 'Pause' : 'Play',
+      child: GestureDetector(
+        onTap: onTap,
+        child: Container(
+          width: 52,
+          height: 52,
+          decoration: const BoxDecoration(
+            color: Color(0x80000000),
+            shape: BoxShape.circle,
+          ),
+          child: Icon(
+            playing ? Icons.pause_rounded : Icons.play_arrow_rounded,
+            color: AppColors.onPrimary,
+            size: 26,
+          ),
+        ),
+      ),
+    );
+  }
+}