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

tests/integration/shop_management_test.go

@@ -11,6 +11,7 @@ import (
 
 	"github.com/break/junhong_cmp_fiber/internal/bootstrap"
 	"github.com/break/junhong_cmp_fiber/internal/model"
+	"github.com/break/junhong_cmp_fiber/internal/model/dto"
 	"github.com/break/junhong_cmp_fiber/internal/routes"
 	"github.com/break/junhong_cmp_fiber/pkg/auth"
 	"github.com/break/junhong_cmp_fiber/pkg/config"
@@ -141,7 +142,7 @@ func TestShopManagement_CreateShop(t *testing.T) {
 	env := setupShopManagementTestEnv(t)
 	defer env.teardown()
 
-	reqBody := model.CreateShopRequest{
+	reqBody := dto.CreateShopRequest{
 		ShopName:     "测试商户",
 		ShopCode:     "TEST001",
 		InitUsername: "testuser",
@@ -191,7 +192,7 @@ func TestShopManagement_CreateShop_DuplicateCode(t *testing.T) {
 	defer env.teardown()
 
 	// 通过 API 创建第一个商户
-	firstReq := model.CreateShopRequest{
+	firstReq := dto.CreateShopRequest{
 		ShopName:     "商户1",
 		ShopCode:     "DUP001",
 		InitUsername: "dupuser1",
@@ -210,7 +211,7 @@ func TestShopManagement_CreateShop_DuplicateCode(t *testing.T) {
 	require.Equal(t, 0, firstResult.Code, "第一个商户应该创建成功")
 
 	// 尝试创建编码重复的商户
-	reqBody := model.CreateShopRequest{
+	reqBody := dto.CreateShopRequest{
 		ShopName:     "商户2",
 		ShopCode:     "DUP001", // 使用相同编码
 		InitUsername: "dupuser2",
@@ -281,7 +282,7 @@ func TestShopManagement_UpdateShop(t *testing.T) {
 	shop := testutil.CreateTestShop(t, env.db, "原始商户", "ORIG001", 1, nil)
 
 	// 更新商户
-	reqBody := model.UpdateShopRequest{
+	reqBody := dto.UpdateShopRequest{
 		ShopName: "更新后的商户",
 		Status:   1,
 	}