fix(flutter): 统一详情页顶部圆形按钮

lib/core/widgets/subpage_header.dart

@@ -21,27 +21,31 @@ const Color _darkBackground = Color(0x59000000);
 const Color _darkShadowColor = Color(0x33000000);
 const Offset _lightShadowOffset = Offset(0, 2);
 
-/// 二级页面统一返回按钮，浅色页使用白底描边，深色页使用半透明黑底。
-class AppSubpageBackButton extends StatelessWidget {
-  const AppSubpageBackButton({
+/// 二级页面统一圆形操作按钮，返回、分享和更多共用同一尺寸与表面样式。
+class AppSubpageCircleButton extends StatelessWidget {
+  const AppSubpageCircleButton({
     super.key,
-    required this.backKey,
+    required this.buttonKey,
+    required this.tooltip,
+    required this.icon,
+    required this.onPressed,
     this.dark = false,
-    this.onBack,
   });
 
-  final Key backKey;
+  final Key buttonKey;
+  final String tooltip;
+  final IconData icon;
+  final VoidCallback onPressed;
   final bool dark;
-  final VoidCallback? onBack;
 
   @override
   Widget build(BuildContext context) {
     return SizedBox(
-      key: backKey,
+      key: buttonKey,
       width: _backSize,
       height: _backSize,
       child: Tooltip(
-        message: MaterialLocalizations.of(context).backButtonTooltip,
+        message: tooltip,
         child: DecoratedBox(
           key: const Key('subpage-back-shadow'),
           decoration: BoxDecoration(
@@ -67,10 +71,10 @@ class AppSubpageBackButton extends StatelessWidget {
             clipBehavior: Clip.antiAlias,
             child: InkWell(
               customBorder: const CircleBorder(),
-              onTap: onBack ?? () => Navigator.of(context).maybePop(),
+              onTap: onPressed,
               child: Center(
                 child: Icon(
-                  Icons.chevron_left_rounded,
+                  icon,
                   color: dark ? Colors.white : AppColors.onSurface,
                   size: _iconSize,
                   weight: _iconWeight,
@@ -84,6 +88,31 @@ class AppSubpageBackButton extends StatelessWidget {
   }
 }
 
+/// 二级页面统一返回按钮，浅色页使用白底描边，深色页使用半透明黑底。
+class AppSubpageBackButton extends StatelessWidget {
+  const AppSubpageBackButton({
+    super.key,
+    required this.backKey,
+    this.dark = false,
+    this.onBack,
+  });
+
+  final Key backKey;
+  final bool dark;
+  final VoidCallback? onBack;
+
+  @override
+  Widget build(BuildContext context) {
+    return AppSubpageCircleButton(
+      buttonKey: backKey,
+      tooltip: MaterialLocalizations.of(context).backButtonTooltip,
+      icon: Icons.chevron_left_rounded,
+      dark: dark,
+      onPressed: onBack ?? () => Navigator.of(context).maybePop(),
+    );
+  }
+}
+
 /// 二级页面统一页头：返回按钮、左对齐标题、可选副标题与右侧操作。
 class AppSubpageHeader extends StatelessWidget {
   const AppSubpageHeader({