feat: 新增配额包/支付相关实体与迁移

App：新增 operation_logs/quota_packages/tenant_payments/tenant_quota_package_purchases 表

Identity：修正 Avatar 字段类型（varchar(256)->text），保持现有数据不变

src/Application/TakeoutSaaS.Application/App/Statistics/Queries/GetRevenueStatisticsQuery.cs

@@ -0,0 +1,15 @@
+using MediatR;
+using TakeoutSaaS.Application.App.Statistics.Dto;
+
+namespace TakeoutSaaS.Application.App.Statistics.Queries;
+
+/// <summary>
+/// 获取收入统计。
+/// </summary>
+public sealed record GetRevenueStatisticsQuery : IRequest<RevenueStatisticsDto>
+{
+    /// <summary>
+    /// 统计月份数量，默认12个月。
+    /// </summary>
+    public int MonthsCount { get; init; } = 12;
+}