fix(orders): filter tax mode before unified order pagination

order/src/main/resources/openapi/order-v1.yaml

@@ -329,6 +329,7 @@ paths:
         relation（仅有关联时返回；PARENT 含 childCount，CHILD 含 rootOrderId、parentOrderId 与 splitSequence）。
         coLoadGroup 仅平台响应返回，由 Order 经 Firstleg 内部批量只读契约聚合；成员业务标识由 Order 权威订单片段补齐。
       parameters:
+        - $ref: '#/components/parameters/UnifiedTaxMode'
         - {name: tenantId, in: query, required: false, schema: {type: string, pattern: '^[1-9][0-9]*$'}}
         - $ref: '#/components/parameters/UnifiedKeyword'
         - $ref: '#/components/parameters/UnifiedOrderNo'
@@ -444,6 +445,7 @@ paths:
         有入库单时同时返回 inboundId、inboundVersion、loadingVersion、pickingVersion；inboundVersion
         才是 C04 loading/complete 的 expectedVersion，loadingVersion 当前等于 pickingVersion（兼容别名）。
       parameters:
+        - $ref: '#/components/parameters/UnifiedTaxMode'
         - $ref: '#/components/parameters/UnifiedKeyword'
         - $ref: '#/components/parameters/UnifiedOrderNo'
         - $ref: '#/components/parameters/UnifiedMainStatus'
@@ -1488,6 +1490,12 @@ components:
       in: query
       required: false
       schema: {type: string, maxLength: 64}
+    UnifiedTaxMode:
+      name: taxMode
+      in: query
+      required: false
+      description: 严格按税务模式在数据库计数和分页前过滤；未传查询全部税务模式，空串或其他值拒绝
+      schema: {type: string, enum: [TAX_REFUND, BUY_DECLARATION]}
     UnifiedOrderNo:
       name: orderNo
       in: query