feat: add coupon checkout support

Tiku.Application/Commerce/CommerceModels.cs

@@ -10,7 +10,8 @@ public sealed record CreateCommerceOrderCommand(
     string? PayMethod,
     string? PayProvider,
     Guid? RegionId,
-    string? CouponCode);
+    string? CouponCode,
+    Guid? CouponRedemptionId);
 
 public sealed record CommerceOrderQuery(int? Limit = null, string? Status = null);
 
@@ -64,6 +65,41 @@ public sealed record CurrentEntitlementItem(
     string Status,
     int? DaysLeft);
 
+public sealed record CommerceCouponQuery(int? Limit = null, string? Status = null);
+
+public sealed record ClaimCommerceCouponCommand(string CouponCode);
+
+public sealed record CheckCommerceCouponCommand(string? CouponCode, Guid? CouponRedemptionId, Guid PlanId, int Quantity, Guid? RegionId);
+
+public sealed record CommerceCouponItem(
+    Guid Id,
+    Guid? CouponId,
+    string CouponCode,
+    string Status,
+    Guid? PlanId,
+    Guid? RegionId,
+    string? DiscountType,
+    decimal? DiscountValue,
+    int? DiscountPreviewCents,
+    string? DiscountPreview,
+    DateTimeOffset? ValidFrom,
+    DateTimeOffset? ValidTo,
+    DateTimeOffset? ClaimedAt,
+    DateTimeOffset? UsedAt);
+
+public sealed record CommerceCouponList(IReadOnlyCollection<CommerceCouponItem> Items);
+
+public sealed record CommerceCouponCheckResult(
+    bool Valid,
+    string? ReasonCode,
+    Guid? CouponId,
+    Guid? CouponRedemptionId,
+    string? CouponCode,
+    int OriginalAmountCents,
+    int DiscountCents,
+    int PayableAmountCents,
+    string PayablePrice);
+
 public sealed record PaymentNotificationProcessResult(
     string Provider,
     string EventId,
@@ -97,6 +133,21 @@ public interface ICommerceService
         CommerceActor actor,
         CancellationToken cancellationToken = default);
 
+    Task<CommerceCouponItem> ClaimCouponAsync(
+        CommerceActor actor,
+        ClaimCommerceCouponCommand command,
+        CancellationToken cancellationToken = default);
+
+    Task<CommerceCouponList> GetCouponsAsync(
+        CommerceActor actor,
+        CommerceCouponQuery query,
+        CancellationToken cancellationToken = default);
+
+    Task<CommerceCouponCheckResult> CheckCouponAsync(
+        CommerceActor actor,
+        CheckCommerceCouponCommand command,
+        CancellationToken cancellationToken = default);
+
     Task<PaymentNotificationProcessResult> ProcessPaymentNotificationAsync(
         Guid tenantId,
         string provider,