feat: setup barrelsby for automatic barrel file generation

Add barrelsby as a dev dependency with a `generate-barrels` npm script and a `barrelesby.json` config targeting `./src`. This automates creation of barrel/index files to simplify imports across the project.

src/data/models/user/credits_history_data.ts

@@ -0,0 +1,57 @@
+/**
+ * 积分历史记录模型 - 对应后端 CreditsHistoryData schema
+ * 原始 Dart: CreditsHistoryData (lib/data/models/user/user.dart)
+ *
+ * 注：原始 Dart 中 `records` 为 `List<Map<String, dynamic>>`，
+ *     迁移为 `Record<string, unknown>[]`。
+ */
+export class CreditsHistoryData {
+  readonly records: Record<string, unknown>[];
+  readonly total: number;
+  readonly limit: number;
+  readonly offset: number;
+
+  constructor(params: {
+    records: Record<string, unknown>[];
+    total: number;
+    limit: number;
+    offset: number;
+  }) {
+    this.records = params.records;
+    this.total = params.total;
+    this.limit = params.limit;
+    this.offset = params.offset;
+    Object.freeze(this);
+  }
+
+  toJson(): Record<string, unknown> {
+    return {
+      records: this.records,
+      total: this.total,
+      limit: this.limit,
+      offset: this.offset,
+    };
+  }
+
+  static fromJson(json: Record<string, unknown>): CreditsHistoryData {
+    const requireNumber = (key: string): number => {
+      const v = json[key];
+      if (typeof v !== "number") {
+        throw new Error(
+          `CreditsHistoryData.${key} is required and must be a number`
+        );
+      }
+      return v;
+    };
+    const rawRecords = json.records;
+    const records: Record<string, unknown>[] = Array.isArray(rawRecords)
+      ? (rawRecords as Record<string, unknown>[])
+      : [];
+    return new CreditsHistoryData({
+      records,
+      total: requireNumber("total"),
+      limit: requireNumber("limit"),
+      offset: requireNumber("offset"),
+    });
+  }
+}