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/Domain/TakeoutSaaS.Domain/Tenants/Entities/OperationLog.cs

@@ -0,0 +1,49 @@
+using TakeoutSaaS.Shared.Abstractions.Entities;
+
+namespace TakeoutSaaS.Domain.Tenants.Entities;
+
+/// <summary>
+/// 运营操作日志。
+/// </summary>
+public sealed class OperationLog : AuditableEntityBase
+{
+    /// <summary>
+    /// 操作类型：BatchExtend, BatchRemind, StatusChange 等。
+    /// </summary>
+    public string OperationType { get; set; } = string.Empty;
+
+    /// <summary>
+    /// 目标类型：Subscription, Bill 等。
+    /// </summary>
+    public string TargetType { get; set; } = string.Empty;
+
+    /// <summary>
+    /// 目标ID列表（JSON）。
+    /// </summary>
+    public string? TargetIds { get; set; }
+
+    /// <summary>
+    /// 操作人ID。
+    /// </summary>
+    public string? OperatorId { get; set; }
+
+    /// <summary>
+    /// 操作人名称。
+    /// </summary>
+    public string? OperatorName { get; set; }
+
+    /// <summary>
+    /// 操作参数（JSON）。
+    /// </summary>
+    public string? Parameters { get; set; }
+
+    /// <summary>
+    /// 操作结果（JSON）。
+    /// </summary>
+    public string? Result { get; set; }
+
+    /// <summary>
+    /// 是否成功。
+    /// </summary>
+    public bool Success { get; set; }
+}

src/Domain/TakeoutSaaS.Domain/Tenants/Entities/QuotaPackage.cs

@@ -0,0 +1,45 @@
+using TakeoutSaaS.Domain.Tenants.Enums;
+using TakeoutSaaS.Shared.Abstractions.Entities;
+
+namespace TakeoutSaaS.Domain.Tenants.Entities;
+
+/// <summary>
+/// 配额包定义（平台提供的可购买配额包）。
+/// </summary>
+public sealed class QuotaPackage : AuditableEntityBase
+{
+    /// <summary>
+    /// 配额包名称。
+    /// </summary>
+    public string Name { get; set; } = string.Empty;
+
+    /// <summary>
+    /// 配额类型。
+    /// </summary>
+    public TenantQuotaType QuotaType { get; set; }
+
+    /// <summary>
+    /// 配额数值。
+    /// </summary>
+    public decimal QuotaValue { get; set; }
+
+    /// <summary>
+    /// 价格。
+    /// </summary>
+    public decimal Price { get; set; }
+
+    /// <summary>
+    /// 是否上架。
+    /// </summary>
+    public bool IsActive { get; set; } = true;
+
+    /// <summary>
+    /// 排序。
+    /// </summary>
+    public int SortOrder { get; set; } = 0;
+
+    /// <summary>
+    /// 描述。
+    /// </summary>
+    public string? Description { get; set; }
+}

src/Domain/TakeoutSaaS.Domain/Tenants/Entities/TenantPayment.cs

@@ -0,0 +1,50 @@
+using TakeoutSaaS.Domain.Tenants.Enums;
+using TakeoutSaaS.Shared.Abstractions.Entities;
+
+namespace TakeoutSaaS.Domain.Tenants.Entities;
+
+/// <summary>
+/// 租户支付记录。
+/// </summary>
+public sealed class TenantPayment : MultiTenantEntityBase
+{
+    /// <summary>
+    /// 关联的账单 ID。
+    /// </summary>
+    public long BillingStatementId { get; set; }
+
+    /// <summary>
+    /// 支付金额。
+    /// </summary>
+    public decimal Amount { get; set; }
+
+    /// <summary>
+    /// 支付方式。
+    /// </summary>
+    public PaymentMethod Method { get; set; }
+
+    /// <summary>
+    /// 支付状态。
+    /// </summary>
+    public PaymentStatus Status { get; set; }
+
+    /// <summary>
+    /// 交易号。
+    /// </summary>
+    public string? TransactionNo { get; set; }
+
+    /// <summary>
+    /// 支付凭证 URL。
+    /// </summary>
+    public string? ProofUrl { get; set; }
+
+    /// <summary>
+    /// 支付时间。
+    /// </summary>
+    public DateTime? PaidAt { get; set; }
+
+    /// <summary>
+    /// 备注信息。
+    /// </summary>
+    public string? Notes { get; set; }
+}

src/Domain/TakeoutSaaS.Domain/Tenants/Entities/TenantQuotaPackagePurchase.cs

@@ -0,0 +1,39 @@
+using TakeoutSaaS.Shared.Abstractions.Entities;
+
+namespace TakeoutSaaS.Domain.Tenants.Entities;
+
+/// <summary>
+/// 租户配额包购买记录。
+/// </summary>
+public sealed class TenantQuotaPackagePurchase : MultiTenantEntityBase
+{
+    /// <summary>
+    /// 配额包 ID。
+    /// </summary>
+    public long QuotaPackageId { get; set; }
+
+    /// <summary>
+    /// 购买时的配额值。
+    /// </summary>
+    public decimal QuotaValue { get; set; }
+
+    /// <summary>
+    /// 购买价格。
+    /// </summary>
+    public decimal Price { get; set; }
+
+    /// <summary>
+    /// 购买时间。
+    /// </summary>
+    public DateTime PurchasedAt { get; set; }
+
+    /// <summary>
+    /// 过期时间（可选）。
+    /// </summary>
+    public DateTime? ExpiredAt { get; set; }
+
+    /// <summary>
+    /// 备注。
+    /// </summary>
+    public string? Notes { get; set; }
+}