refactor(vo): 重构VO类及相关模型，添加Voable接口实现

feat(constant): 添加WebSocket错误码常量
docs(model): 为模型类添加注释
fix(service): 修复ProductUsageService缓存键问题
refactor(converter): 重构字符串转换器，移除EntityStringConverter依赖
feat(tab): 添加ComboBoxUtils工具类，优化下拉框初始化
style: 移除无用导入和字段

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

@@ -6,6 +6,8 @@ import java.util.Objects;
 import org.hibernate.annotations.ColumnDefault;
 
 import com.ecep.contract.util.HibernateProxyUtils;
+import com.ecep.contract.vo.ProjectQuotationVo;
+import com.ecep.contract.model.Voable;
 
 import jakarta.persistence.Column;
 import jakarta.persistence.Entity;
@@ -30,7 +32,7 @@ import lombok.ToString;
 @Entity
 @Table(name = "PROJECT_QUOTATION")
 @ToString
-public class ProjectQuotation implements IdentityEntity, ProjectBasedEntity, java.io.Serializable {
+public class ProjectQuotation implements IdentityEntity, ProjectBasedEntity, java.io.Serializable, Voable<ProjectQuotationVo> {
     private static final long serialVersionUID = 1L;
     @Id
     @GeneratedValue(strategy = GenerationType.IDENTITY)
@@ -132,4 +134,31 @@ public class ProjectQuotation implements IdentityEntity, ProjectBasedEntity, jav
         return HibernateProxyUtils.hashCode(this);
     }
 
+    @Override
+    public ProjectQuotationVo toVo() {
+        ProjectQuotationVo vo = new ProjectQuotationVo();
+        vo.setId(id);
+        if (project != null) {
+            vo.setProject(project.getId());
+        }
+        vo.setLevel(level);
+        vo.setStandardPayWay(standardPayWay);
+        vo.setNoStandardPayWayText(noStandardPayWayText);
+        vo.setAmount(amount);
+        if (applicant != null) {
+            vo.setApplicantId(applicant.getId());
+        }
+        vo.setApplyTime(applyTime);
+        if (authorizer != null) {
+            vo.setAuthorizerId(authorizer.getId());
+        }
+        vo.setAuthorizationTime(authorizationTime);
+        vo.setAuthorizationFile(authorizationFile);
+        vo.setDescription(description);
+        if (evaluationFile != null) {
+            vo.setEvaluationFileId(evaluationFile.getId());
+        }
+        // active字段默认为false，在ProjectQuotationVo类中已经设置
+        return vo;
+    }
 }