fix: 修复编译错误（重复字段 + 缺失import + 参数不匹配）

- MembershipLevel.java: 删除重复的 priceQuarterly 字段
- PaymentOrder.java: 删除重复的 period 字段
- MembershipLevelDTO.java: 删除重复 priceQuarterly，补回缺失的 priceYearly
- MigrationController.java: 添加缺失的 java.util.Date import
- MembershipController.java: createOrder 调用补第6个参数

cfc-backend/src/main/java/com/etotem/cfc/controller/MembershipController.java

@@ -192,7 +192,7 @@ public class MembershipController {
         }
 
         Long familyId = membershipService.getUserFamilyId(userId);
-        PaymentOrderDTO order = membershipService.createOrder(userId, familyId, "FAMILY", "trial", null);
+        PaymentOrderDTO order = membershipService.createOrder(userId, familyId, "FAMILY", "trial", null, null);
         return Result.success(order);
     }
 

cfc-backend/src/main/java/com/etotem/cfc/controller/admin/MigrationController.java

@@ -7,6 +7,7 @@ import org.springframework.jdbc.core.JdbcTemplate;
 import org.springframework.web.bind.annotation.*;
 
 import javax.annotation.Resource;
+import java.util.Date;
 import java.util.List;
 import java.util.Map;
 import java.util.stream.Collectors;

cfc-backend/src/main/java/com/etotem/cfc/dto/MembershipLevelDTO.java

@@ -12,7 +12,6 @@ public class MembershipLevelDTO {
     private Integer priceMonthly;
     private Integer priceQuarterly;
     private Integer priceYearly;
-    private Integer priceQuarterly;
     private String features;
     private Integer maxChildren;
     private Integer maxTasksPerDay;

cfc-backend/src/main/java/com/etotem/cfc/entity/MembershipLevel.java

@@ -27,8 +27,6 @@ public class MembershipLevel implements Serializable {
 
     private Integer priceYearly;  // 年费（分）
 
-    private Integer priceQuarterly;  // 季费（分）
-
     private String features;  // 功能权限列表(JSON)
 
     private Integer maxChildren;  // 可添加孩子数量

cfc-backend/src/main/java/com/etotem/cfc/entity/PaymentOrder.java

@@ -40,6 +40,4 @@ public class PaymentOrder implements Serializable {
     private Date createdAt;
 
     private Date updatedAt;
-
-    private String period;  // subscription period: monthly/quarterly/yearly/family
 }