适配平板

lib/widgets/master_detail_scaffold.dart

@@ -0,0 +1,36 @@
+import 'package:flutter/material.dart';
+import '../utils/responsive.dart';
+
+/// Master-Detail 布局包装器
+/// 手机或 detail 为 null 时只显示 master；平板显示左右分栏
+class MasterDetailScaffold extends StatelessWidget {
+  final Widget master;
+  final Widget? detail;
+  final double masterFraction;
+  final double minMasterWidth;
+
+  const MasterDetailScaffold({
+    super.key,
+    required this.master,
+    this.detail,
+    this.masterFraction = 0.38,
+    this.minMasterWidth = 320,
+  });
+
+  @override
+  Widget build(BuildContext context) {
+    if (!Breakpoint.isWideContent(context) || detail == null) {
+      return master;
+    }
+    final screenWidth = MediaQuery.sizeOf(context).width;
+    final effectiveMasterWidth =
+        (screenWidth * masterFraction).clamp(minMasterWidth, screenWidth * 0.5);
+    return Row(
+      children: [
+        SizedBox(width: effectiveMasterWidth, child: master),
+        const VerticalDivider(width: 0.5, thickness: 0.5),
+        Expanded(child: detail!),
+      ],
+    );
+  }
+}