feat(aftersale): per-line refund/return flow with ledger-backed completion (add-aftersale-refunds)

apps/api/src/models.rs

@@ -173,6 +173,8 @@ pub struct Order {
     pub total_minor: i64,
     /// Realized coupon discount, converted to the order currency server-side.
     pub discount_minor: i64,
+    /// Authoritative sum of completed after-sale refunds.
+    pub refund_total_minor: i64,
     /// The coupon this order redeemed, if any.
     pub coupon_id: Option<Uuid>,
     /// Group-buying activity this order joined, if any.
@@ -198,6 +200,36 @@ pub struct OrderItem {
     pub flash_sale_item_id: Option<Uuid>,
 }
 
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize, Type)]
+#[sqlx(type_name = "aftersale_kind", rename_all = "snake_case")]
+#[serde(rename_all = "snake_case")]
+pub enum AftersaleKind {
+    RefundOnly,
+    ReturnRefund,
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize, Type)]
+#[sqlx(type_name = "aftersale_status", rename_all = "snake_case")]
+#[serde(rename_all = "snake_case")]
+pub enum AftersaleStatus {
+    Pending,
+    Approved,
+    Rejected,
+    BuyerShipping,
+    MerchantConfirmed,
+    Refunded,
+    Cancelled,
+}
+
+impl AftersaleStatus {
+    pub fn is_terminal(self) -> bool {
+        matches!(
+            self,
+            AftersaleStatus::Refunded | AftersaleStatus::Rejected | AftersaleStatus::Cancelled
+        )
+    }
+}
+
 #[derive(Debug, Clone, Serialize, sqlx::FromRow)]
 pub struct Shipment {
     pub id: Uuid,