refactor(vo): 重构VO对象结构，统一字段命名和接口实现

重构所有VO对象，统一字段命名规范，移除冗余字段，优化接口实现
新增Voable接口用于VO对象转换
调整BaseViewModel和ProjectBasedViewModel接口定义
更新相关服务和控制器以适应VO对象变更

common/src/main/java/com/ecep/contract/model/ContractItem.java

@@ -6,6 +6,7 @@ import java.time.LocalDateTime;
 import java.util.Objects;
 
 import com.ecep.contract.util.HibernateProxyUtils;
+import com.ecep.contract.vo.ContractItemVo;
 
 import jakarta.persistence.Column;
 import jakarta.persistence.Entity;
@@ -28,7 +29,8 @@ import lombok.ToString;
 @Entity
 @Table(name = "CONTRACT_ITEM")
 @ToString
-public class ContractItem implements IdentityEntity, ContractBasedEntity, BasedEntity, Serializable {
+public class ContractItem
+        implements IdentityEntity, ContractBasedEntity, BasedEntity, Serializable, Voable<ContractItemVo> {
     private static final long serialVersionUID = 1L;
     @Id
     @GeneratedValue(strategy = GenerationType.IDENTITY)
@@ -162,4 +164,37 @@ public class ContractItem implements IdentityEntity, ContractBasedEntity, BasedE
     public final int hashCode() {
         return HibernateProxyUtils.hashCode(this);
     }
+
+    @Override
+    public ContractItemVo toVo() {
+        ContractItemVo vo = new ContractItemVo();
+        vo.setId(id);
+        if (contract != null) {
+            vo.setContractId(contract.getId());
+        }
+        vo.setRefId(refId);
+        vo.setItemCode(itemCode);
+        vo.setTitle(title);
+        vo.setSpecification(specification);
+        vo.setUnit(unit);
+        if (inventory != null) {
+            vo.setInventoryId(inventory.getId());
+        }
+        vo.setExclusiveTaxPrice(exclusiveTaxPrice);
+        vo.setTaxRate(taxRate);
+        vo.setTaxPrice(taxPrice);
+        vo.setQuantity(quantity);
+        vo.setCreateDate(createDate);
+        vo.setUpdateDate(updateDate);
+        vo.setStartDate(startDate);
+        vo.setEndDate(endDate);
+        if (creator != null) {
+            vo.setCreatorId(creator.getId());
+        }
+        if (updater != null) {
+            vo.setUpdaterId(updater.getId());
+        }
+        vo.setRemark(remark);
+        return vo;
+    }
 }