feat: add signed PostgreSQL release updates

oa-backend/src/main/java/com/kaidi/oa/domain/Financing.java

@@ -42,7 +42,7 @@ public class Financing {
     private String currency;
 
     /** 年化利率（百分比，如 4.35 表示 4.35%）。 */
-    private Double rate;
+    private BigDecimal rate;
 
     private String startDate;
 
@@ -122,11 +122,11 @@ public class Financing {
         this.currency = currency;
     }
 
-    public Double getRate() {
+    public BigDecimal getRate() {
         return rate;
     }
 
-    public void setRate(Double rate) {
+    public void setRate(BigDecimal rate) {
         this.rate = rate;
     }