Implement batch fee management features in BillingController, including preview, submission, and task retrieval. Update related services and mappers to support batch processing. Add necessary error messages in properties file and enhance front-end API for batch operations.

bms-back/bms-system/src/main/java/com/bms/price/mapper/PrcIncomeBillFeeMapper.java

@@ -17,6 +17,10 @@ public interface PrcIncomeBillFeeMapper
 
     public PrcIncomeBillFee selectByFeeId(String feeId);
 
+    /** Lookup by unique key uk_bill_fee_item (bill_id, fee_type, sc_id). */
+    public PrcIncomeBillFee selectByBillIdAndFeeTypeAndScId(@Param("billId") String billId,
+        @Param("feeType") String feeType, @Param("scId") Long scId);
+
     /** Count fees of a bill under given ar_bill_status and fee_type (e.g. BILLED + BASIC_FREIGHT). */
     public int countByBillIdAndArBillStatusAndFeeType(@Param("billId") String billId,
         @Param("arBillStatus") String arBillStatus, @Param("feeType") String feeType);