feat: 完善手动创建租户功能，添加账单明细和支付记录

1. 手动创建租户时自动生成账单明细（LineItemsJson）
2. 账单状态为已支付时自动创建支付记录
3. 租户列表接口返回联系人信息和认证状态
4. 账单详情接口返回支付记录和解析后的账单明细
5. 管理员账号自动复用租户联系人信息

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

src/Application/TakeoutSaaS.Application/App/Billings/Contracts/BillingDetailDto.cs

@@ -86,6 +86,11 @@ public sealed record BillingDetailDto
     /// </summary>
     public string? LineItemsJson { get; init; }
 
+    /// <summary>
+    /// 账单明细列表（从 LineItemsJson 解析）。
+    /// </summary>
+    public IReadOnlyList<BillingLineItemDto>? LineItems { get; init; }
+
     /// <summary>
     /// 备注。
     /// </summary>
@@ -195,3 +200,34 @@ public sealed record PaymentRecordDto
     /// </summary>
     public DateTime CreatedAt { get; init; }
 }
+
+/// <summary>
+/// 账单明细项 DTO。
+/// </summary>
+public sealed record BillingLineItemDto
+{
+    /// <summary>
+    /// 项目名称。
+    /// </summary>
+    public string Name { get; init; } = string.Empty;
+
+    /// <summary>
+    /// 单价。
+    /// </summary>
+    public decimal UnitPrice { get; init; }
+
+    /// <summary>
+    /// 数量。
+    /// </summary>
+    public int Quantity { get; init; }
+
+    /// <summary>
+    /// 金额。
+    /// </summary>
+    public decimal Amount { get; init; }
+
+    /// <summary>
+    /// 备注。
+    /// </summary>
+    public string? Remark { get; init; }
+}

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

@@ -1,3 +1,4 @@
+using System.Text.Json;
 using MediatR;
 using TakeoutSaaS.Application.App.Billings.Contracts;
 using TakeoutSaaS.Application.App.Billings.Queries;
@@ -25,7 +26,43 @@ public sealed class GetBillingDetailQueryHandler(IBillingRepository billingRepos
             return null;
         }
 
-        // 3. 映射为 DTO 并返回（支付记录暂时返回空列表）
+        // 3. 查询支付记录
+        var payments = await billingRepository.GetPaymentsByBillingIdAsync(request.BillingId, cancellationToken);
+
+        // 4. 映射支付记录为 DTO
+        var paymentDtos = payments.Select(p => new PaymentRecordDto
+        {
+            Id = p.Id,
+            BillingStatementId = p.BillingStatementId,
+            Amount = p.Amount,
+            Method = (int)p.Method,
+            Status = (int)p.Status,
+            TransactionNo = p.TransactionNo,
+            ProofUrl = p.ProofUrl,
+            PaidAt = p.PaidAt,
+            Notes = p.Notes,
+            VerifiedBy = p.VerifiedBy,
+            VerifiedAt = p.VerifiedAt,
+            RefundReason = p.RefundReason,
+            RefundedAt = p.RefundedAt,
+            CreatedAt = p.CreatedAt
+        }).ToList();
+
+        // 5. 解析账单明细 JSON
+        List<BillingLineItemDto>? lineItems = null;
+        if (!string.IsNullOrEmpty(detail.LineItemsJson))
+        {
+            try
+            {
+                lineItems = JsonSerializer.Deserialize<List<BillingLineItemDto>>(detail.LineItemsJson);
+            }
+            catch
+            {
+                // 解析失败时忽略
+            }
+        }
+
+        // 6. 映射为 DTO 并返回
         return new BillingDetailDto
         {
             Id = detail.Id,
@@ -43,12 +80,13 @@ public sealed class GetBillingDetailQueryHandler(IBillingRepository billingRepos
             Status = detail.Status,
             DueDate = detail.DueDate,
             LineItemsJson = detail.LineItemsJson,
+            LineItems = lineItems,
             Notes = detail.Notes,
             OverdueNotifiedAt = detail.OverdueNotifiedAt,
             ReminderSentAt = detail.ReminderSentAt,
             CreatedAt = detail.CreatedAt,
             UpdatedAt = detail.UpdatedAt,
-            Payments = []
+            Payments = paymentDtos
         };
     }
 }