feat(admin): 新增管理员角色、账单、订阅、套餐管理功能

- 新增 AdminRolesController 实现角色 CRUD 和权限管理
- 新增 BillingsController 实现账单查询功能
- 新增 SubscriptionsController 实现订阅管理功能
- 新增 TenantPackagesController 实现套餐管理功能
- 新增租户详情、配额使用、账单列表等查询功能
- 新增 TenantPackage、TenantSubscription 等领域实体
- 新增相关枚举：SubscriptionStatus、TenantPackageType 等
- 更新 appsettings 配置文件
- 更新权限授权策略提供者

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/Application/TakeoutSaaS.Application/App/Billings/Handlers/ConfirmPaymentCommandHandler.cs

@@ -0,0 +1,92 @@
+using MediatR;
+using TakeoutSaaS.Application.App.Billings.Commands;
+using TakeoutSaaS.Application.App.Billings.Contracts;
+using TakeoutSaaS.Domain.Billings.Entities;
+using TakeoutSaaS.Domain.Billings.Enums;
+using TakeoutSaaS.Domain.Billings.Repositories;
+using TakeoutSaaS.Shared.Abstractions.Security;
+
+namespace TakeoutSaaS.Application.App.Billings.Handlers;
+
+/// <summary>
+/// 确认收款命令处理器。
+/// </summary>
+public sealed class ConfirmPaymentCommandHandler(
+    IBillingRepository billingRepository,
+    ICurrentUserAccessor currentUserAccessor)
+    : IRequestHandler<ConfirmPaymentCommand, PaymentRecordDto?>
+{
+    /// <inheritdoc />
+    public async Task<PaymentRecordDto?> Handle(
+        ConfirmPaymentCommand request,
+        CancellationToken cancellationToken)
+    {
+        // 1. 获取账单（带跟踪）
+        var billing = await billingRepository.GetByIdForUpdateAsync(request.BillingId, cancellationToken);
+
+        // 2. 如果不存在，返回 null
+        if (billing is null)
+        {
+            return null;
+        }
+
+        // 3. 获取当前用户 ID
+        var currentUserId = currentUserAccessor.UserId;
+        var now = DateTime.UtcNow;
+
+        // 4. 创建支付记录（已审核通过状态）
+        var payment = new TenantPayment
+        {
+            TenantId = billing.TenantId,
+            BillingStatementId = billing.Id,
+            Amount = request.Amount,
+            Method = request.Method,
+            Status = TenantPaymentStatus.Success,
+            TransactionNo = request.TransactionNo,
+            ProofUrl = request.ProofUrl,
+            Notes = request.Notes,
+            PaidAt = now,
+            VerifiedBy = currentUserId,
+            VerifiedAt = now,
+            CreatedAt = now,
+            CreatedBy = currentUserId
+        };
+
+        // 5. 添加支付记录
+        await billingRepository.AddPaymentAsync(payment, cancellationToken);
+
+        // 6. 更新账单已付金额
+        billing.AmountPaid += request.Amount;
+
+        // 7. 如果已付金额 >= 应付金额，更新账单状态为已支付
+        if (billing.AmountPaid >= billing.AmountDue)
+        {
+            billing.Status = TenantBillingStatus.Paid;
+        }
+
+        // 8. 更新账单时间戳
+        billing.UpdatedAt = now;
+
+        // 9. 保存变更
+        await billingRepository.SaveChangesAsync(cancellationToken);
+
+        // 10. 返回支付记录 DTO
+        return new PaymentRecordDto
+        {
+            Id = payment.Id,
+            BillingStatementId = payment.BillingStatementId,
+            Amount = payment.Amount,
+            Method = (int)payment.Method,
+            Status = (int)payment.Status,
+            TransactionNo = payment.TransactionNo,
+            ProofUrl = payment.ProofUrl,
+            PaidAt = payment.PaidAt,
+            Notes = payment.Notes,
+            VerifiedBy = payment.VerifiedBy,
+            VerifiedAt = payment.VerifiedAt,
+            RefundReason = payment.RefundReason,
+            RefundedAt = payment.RefundedAt,
+            CreatedAt = payment.CreatedAt
+        };
+    }
+}