feat:"初始化仓库，并更新基础代码。"

lib/models/category_model.dart

@@ -0,0 +1,39 @@
+class Category {
+  final int? id;
+  final String name;
+  final String type; // 'income' or 'expense'
+  final String icon;
+  final int color;
+  final int? parentId; // 支持多级分类
+
+  Category({
+    this.id,
+    required this.name,
+    required this.type,
+    required this.icon,
+    required this.color,
+    this.parentId,
+  });
+
+  Map<String, dynamic> toMap() {
+    return {
+      'id': id,
+      'name': name,
+      'type': type,
+      'icon': icon,
+      'color': color,
+      'parentId': parentId,
+    };
+  }
+
+  factory Category.fromMap(Map<String, dynamic> map) {
+    return Category(
+      id: map['id'],
+      name: map['name'],
+      type: map['type'],
+      icon: map['icon'],
+      color: map['color'],
+      parentId: map['parentId'],
+    );
+  }
+}