fix(firstleg): persist pricing conversion metadata

firstleg/src/main/resources/openapi/fba-pricing-v1.yaml

@@ -282,7 +282,7 @@ components:
     FeeSnapshotResponse:
       type: object
       description: fl_inbound_fee 当前版本快照；自动初算为 CALCULATED，人工确认后为 CONFIRMED，只有人工发布后为 SENT。
-      required: [feeId, feeNo, feeVersion, feeStatus, inboundId, totalAmount, currency]
+      required: [feeId, feeNo, feeVersion, feeStatus, inboundId, conversionFactor, roundingScale, roundingMode, totalAmount, currency]
       properties:
         feeId: {type: string, pattern: '^[1-9][0-9]*$'}
         feeNo: {type: string}
@@ -312,9 +312,9 @@ components:
         taxMode: {type: string, nullable: true}
         pricingTaxMode: {type: string, nullable: true}
         chargeMode: {type: string, nullable: true}
-        conversionFactor: {type: number, nullable: true}
-        roundingScale: {type: integer, nullable: true}
-        roundingMode: {type: string, nullable: true}
+        conversionFactor: {type: number, description: 本费用版本实际使用的重量体积换算系数；FBA/区域重量阶梯按KG为167，FBA按CBM为363}
+        roundingScale: {type: integer, enum: [6], description: 本费用版本最终计费量实际保留的小数位数}
+        roundingMode: {type: string, enum: [HALF_UP], description: 本费用版本最终计费量实际使用的舍入方式}
         actualWeightKg: {type: number, nullable: true}
         actualVolumeCbm: {type: number, nullable: true}
         convertedQuantity: {type: number, nullable: true}