feat(order): 支持订单详情手动添加费用项

新增 OrderFeeAddInput 并在 OrderEdit 服务中实现费用追加逻辑，配合前端订单详情抽屉添加费用能力。

Co-authored-by: Cursor <cursoragent@cursor.com>

src/Oms.Application/Dtos/Orders/OrderFeeAddInput.cs

@@ -0,0 +1,66 @@
+using System.ComponentModel.DataAnnotations;
+
+namespace Oms.Application.Dtos.Orders;
+
+/// <summary>
+/// 手动添加订单费用入参。
+/// </summary>
+public class OrderFeeAddInput
+{
+    /// <summary>
+    /// 订单主键。
+    /// </summary>
+    [Required]
+    public int Id { get; set; }
+
+    /// <summary>
+    /// 费用类型：receivable / payable。
+    /// </summary>
+    [Required]
+    [StringLength(16)]
+    public string Type { get; set; } = string.Empty;
+
+    /// <summary>
+    /// 费用项编码。
+    /// </summary>
+    [Required]
+    [StringLength(64)]
+    public string CostItem { get; set; } = string.Empty;
+
+    /// <summary>
+    /// 金额。
+    /// </summary>
+    [Required]
+    public decimal Amount { get; set; }
+
+    /// <summary>
+    /// 币种。
+    /// </summary>
+    [Required]
+    [StringLength(16)]
+    public string Currency { get; set; } = string.Empty;
+
+    /// <summary>
+    /// 计费阶段：forecast / inbound / outbound。
+    /// </summary>
+    [Required]
+    [StringLength(16)]
+    public string ChargingStage { get; set; } = string.Empty;
+
+    /// <summary>
+    /// 下游服务商（应付可选）。
+    /// </summary>
+    [StringLength(128)]
+    public string? DownstreamProvider { get; set; }
+
+    /// <summary>
+    /// 价格编号（可选）。
+    /// </summary>
+    [StringLength(64)]
+    public string? PriceNo { get; set; }
+
+    /// <summary>
+    /// 价格生效时间（可选）。
+    /// </summary>
+    public DateTime? PriceEffectiveTime { get; set; }
+}

src/Oms.Application/Services/Orders/OrderService.OrderEdit.cs

@@ -233,6 +233,69 @@ public partial class OrderService
         return (await MapOrderOutputsAsync([order])).First();
     }
 
+    /// <summary>
+    /// 手动添加订单费用（应收或应付）。
+    /// </summary>
+    [HttpPost("/order/fee/add")]
+    public async Task<OrderOutput> AddOrderFeeAsync(OrderFeeAddInput input)
+    {
+        var order = await GetOrderOrThrowAsync(input.Id);
+
+        var type = input.Type?.Trim().ToLowerInvariant() ?? string.Empty;
+        if (type is not (OrderFeeTypeCodes.Receivable or OrderFeeTypeCodes.Payable))
+        {
+            throw new BusinessException("费用类型无效");
+        }
+
+        var costItem = input.CostItem?.Trim() ?? string.Empty;
+        if (string.IsNullOrWhiteSpace(costItem))
+        {
+            throw new BusinessException("费用项不能为空");
+        }
+
+        if (input.Amount <= 0)
+        {
+            throw new BusinessException("金额必须大于0");
+        }
+
+        var currency = input.Currency?.Trim() ?? string.Empty;
+        if (string.IsNullOrWhiteSpace(currency))
+        {
+            throw new BusinessException("币种不能为空");
+        }
+
+        var chargingStage = input.ChargingStage?.Trim() ?? string.Empty;
+        if (chargingStage is not (
+            OrderFeeChargingStageCodes.Forecast
+            or OrderFeeChargingStageCodes.Inbound
+            or OrderFeeChargingStageCodes.Outbound))
+        {
+            throw new BusinessException("计费阶段无效");
+        }
+
+        var fee = new OrderFee
+        {
+            Type = type,
+            CostItem = costItem,
+            Amount = input.Amount,
+            Currency = currency,
+            ChargingStage = chargingStage,
+            DownstreamProvider = string.IsNullOrWhiteSpace(input.DownstreamProvider)
+                ? null
+                : input.DownstreamProvider.Trim(),
+            PriceNo = string.IsNullOrWhiteSpace(input.PriceNo) ? null : input.PriceNo.Trim(),
+            PriceEffectiveTime = input.PriceEffectiveTime,
+            CreateTime = DateTime.Now,
+            UpdateTime = DateTime.Now,
+        };
+
+        await OrderRepository.UpsertFeesAsync(order.Id, [fee]);
+        order.UpdateTime = DateTime.Now;
+        await OrderRepository.UpdateAsync(order);
+
+        return (await MapOrderOutputsAsync([order])).First();
+    }
+
     private async Task RecalculateReceivableCoreAsync(Order order)
     {
         if (string.IsNullOrWhiteSpace(order.ProductCode))