fix(finance): stabilize settlement idempotency request hashes

finance/src/main/java/com/baiyue/finance/service/FinanceSettlementService.java

@@ -12,6 +12,7 @@ import com.baiyue.finance.dto.FinanceSettlementDtos.SettlementActionRequest;
 import com.fasterxml.jackson.core.type.TypeReference;
 import com.fasterxml.jackson.databind.JsonNode;
 import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.SerializationFeature;
 import org.slf4j.MDC;
 import org.springframework.jdbc.core.JdbcTemplate;
 import org.springframework.jdbc.support.GeneratedKeyHolder;
@@ -523,10 +524,13 @@ public class FinanceSettlementService {
         return documentNumbers.next("PAY");
     }
 
+    /** 固定映射键序，避免 JVM 重启改变 Map.of 遍历顺序而误拒绝原请求。 */
     private String hash(Object value) {
         try {
+            String canonical = objectMapper.writer()
+                .with(SerializationFeature.ORDER_MAP_ENTRIES_BY_KEYS).writeValueAsString(value);
             return HexFormat.of().formatHex(MessageDigest.getInstance("SHA-256")
-                .digest(json(value).getBytes(StandardCharsets.UTF_8)));
+                .digest(canonical.getBytes(StandardCharsets.UTF_8)));
         } catch (Exception failure) {
             throw error("FIN_001", "幂等请求哈希失败");
         }