feat(points): 实现积分流水列表功能

- 后端新增 GET /api/v1/points/ledger 接口
- 前端新增积分流水列表页面
- 积分中心添加「查看流水」入口
- 重命名 AccountDeleteScreen 为 AccountDataScreen
- 流水列表支持分页加载和空状态展示

apps/lib/features/points/data/apis/points_api.dart

@@ -1,5 +1,6 @@
 import 'package:dio/dio.dart';
 
+import '../models/ledger_item.dart';
 import '../models/package_info.dart';
 
 class PointsApi {
@@ -11,4 +12,19 @@ class PointsApi {
     final response = await _dio.get('/api/v1/points/packages');
     return PackagesResult.fromJson(response.data as Map<String, dynamic>);
   }
+
+  Future<LedgerListResult> getLedger({
+    int limit = 20,
+    String? cursor,
+  }) async {
+    final query = <String, dynamic>{'limit': limit};
+    if (cursor != null) {
+      query['cursor'] = cursor;
+    }
+    final response = await _dio.get(
+      '/api/v1/points/ledger',
+      queryParameters: query,
+    );
+    return LedgerListResult.fromJson(response.data as Map<String, dynamic>);
+  }
 }

apps/lib/features/points/data/models/ledger_item.dart

@@ -0,0 +1,50 @@
+class LedgerItem {
+  const LedgerItem({
+    required this.id,
+    required this.direction,
+    required this.amount,
+    required this.balanceAfter,
+    required this.changeType,
+    required this.createdAt,
+  });
+
+  final String id;
+  final int direction;
+  final int amount;
+  final int balanceAfter;
+  final String changeType;
+  final String createdAt;
+
+  factory LedgerItem.fromJson(Map<String, dynamic> json) {
+    return LedgerItem(
+      id: json['id'] as String,
+      direction: json['direction'] as int,
+      amount: json['amount'] as int,
+      balanceAfter: json['balanceAfter'] as int,
+      changeType: json['changeType'] as String,
+      createdAt: json['createdAt'] as String,
+    );
+  }
+}
+
+class LedgerListResult {
+  const LedgerListResult({
+    required this.items,
+    this.nextCursor,
+    required this.hasMore,
+  });
+
+  final List<LedgerItem> items;
+  final String? nextCursor;
+  final bool hasMore;
+
+  factory LedgerListResult.fromJson(Map<String, dynamic> json) {
+    return LedgerListResult(
+      items: (json['items'] as List<dynamic>)
+          .map((e) => LedgerItem.fromJson(e as Map<String, dynamic>))
+          .toList(),
+      nextCursor: json['nextCursor'] as String?,
+      hasMore: json['hasMore'] as bool,
+    );
+  }
+}