refactor: 将 DTO 文件从 internal/model 移动到 internal/model/dto 目录

- 移动 17 个 DTO 文件到 internal/model/dto/ 目录
- 更新所有 DTO 文件的 package 声明从 model 改为 dto
- 更新所有引用文件的 import 和类型引用
  - Handler 层：admin 和 h5 所有处理器
  - Service 层：所有业务服务
  - Routes 层：所有路由定义
  - Tests 层：单元测试和集成测试
- 清理未使用的 import 语句
- 验证：项目构建成功，测试编译通过，LSP 无错误

internal/handler/admin/commission_withdrawal.go

@@ -5,7 +5,7 @@ import (
 
 	"github.com/gofiber/fiber/v2"
 
-	"github.com/break/junhong_cmp_fiber/internal/model"
+	"github.com/break/junhong_cmp_fiber/internal/model/dto"
 	commissionWithdrawalService "github.com/break/junhong_cmp_fiber/internal/service/commission_withdrawal"
 	"github.com/break/junhong_cmp_fiber/pkg/errors"
 	"github.com/break/junhong_cmp_fiber/pkg/response"
@@ -20,7 +20,7 @@ func NewCommissionWithdrawalHandler(service *commissionWithdrawalService.Service
 }
 
 func (h *CommissionWithdrawalHandler) ListWithdrawalRequests(c *fiber.Ctx) error {
-	var req model.WithdrawalRequestListReq
+	var req dto.WithdrawalRequestListReq
 	if err := c.QueryParser(&req); err != nil {
 		return errors.New(errors.CodeInvalidParam, "请求参数解析失败")
 	}
@@ -39,7 +39,7 @@ func (h *CommissionWithdrawalHandler) ApproveWithdrawal(c *fiber.Ctx) error {
 		return errors.New(errors.CodeInvalidParam, "无效的提现申请ID")
 	}
 
-	var req model.ApproveWithdrawalReq
+	var req dto.ApproveWithdrawalReq
 	if err := c.BodyParser(&req); err != nil {
 		return errors.New(errors.CodeInvalidParam, "请求参数解析失败")
 	}
@@ -58,7 +58,7 @@ func (h *CommissionWithdrawalHandler) RejectWithdrawal(c *fiber.Ctx) error {
 		return errors.New(errors.CodeInvalidParam, "无效的提现申请ID")
 	}
 
-	var req model.RejectWithdrawalReq
+	var req dto.RejectWithdrawalReq
 	if err := c.BodyParser(&req); err != nil {
 		return errors.New(errors.CodeInvalidParam, "请求参数解析失败")
 	}