refactor: Controller 不直接读 Session Exp，新增 CanCreatePost 方法

- 新增 userExpReader 最小接口（ISP），PostService 通过它读取用户经验值
- PostService 新增 CanCreatePost(userID uint) bool，封装 LV0 投稿权限判断
- StudioController 替换内联 c.Get("exp") 检查为调用 ctrl.postService.CanCreatePost(uid)
- 更新 DI 注入链：NewPostService 增加 userRepo 参数

internal/controller/interfaces.go

@@ -40,7 +40,7 @@ type postUseCase interface {
 	IsPostAccessible(userID uint, role string, postUserID uint) bool
 }
 
-// studioUseCase StudioController 对 PostService 的最小依赖（ISP：8 个方法）
+// studioUseCase StudioController 对 PostService 的最小依赖（ISP：9 个方法）
 type studioUseCase interface {
 	Create(userID uint, title, body string) (*model.Post, error)
 	GetByID(id uint) (*model.Post, error)
@@ -50,6 +50,7 @@ type studioUseCase interface {
 	ListByUser(userID uint, status string, page, pageSize int) ([]model.Post, int64, error)
 	GetOverview(userID uint) (*service.StudioOverview, error)
 	IsPostAccessible(userID uint, role string, postUserID uint) bool
+	CanCreatePost(userID uint) bool
 }
 
 // spaceUseCase SpaceController 对 SpaceService 的最小依赖（ISP：5 个方法）

internal/controller/studio_post_api_controller.go

@@ -19,12 +19,10 @@ func (ctrl *StudioController) Create(c *gin.Context) {
 	}
 
 	// LV0 用户不允许投稿
-	if expVal, exists := c.Get("exp"); exists {
-		if exp, ok := expVal.(int); ok && exp < 1 {
+	if !ctrl.postService.CanCreatePost(uid) {
 		common.Error(c, http.StatusForbidden, "经验不足，Lv1 解锁投稿")
 		return
 	}
-	}
 
 	var req model.PostCreateRequest
 	if err := c.ShouldBindJSON(&req); err != nil {

internal/router/deps_extra.go

@@ -51,7 +51,7 @@ func buildDeps(db *gorm.DB, cfg *config.Config, siteSettings *config.SiteSetting
 	)
 
 	postRepo := repository.NewPostRepo(db)
-	postService := service.NewPostService(postRepo, siteSettings, notificationService)
+	postService := service.NewPostService(postRepo, siteSettings, notificationService, userRepo)
 	shortcodeSvc := service.NewShortcodeService()
 	postCtrl := controller.NewPostController(postService, shortcodeSvc)
 	adminPostCtrl := adminCtrl.NewAdminPostController(postService)

internal/service/post_service.go

@@ -16,14 +16,16 @@ type PostService struct {
 	repo     postStore
 	ss       *config.SiteSettings
 	notifier postNotifier
+	userRepo userExpReader
 }
 
 // NewPostService 构造函数
-func NewPostService(repo postStore, ss *config.SiteSettings, notifier postNotifier) *PostService {
+func NewPostService(repo postStore, ss *config.SiteSettings, notifier postNotifier, userRepo userExpReader) *PostService {
 	return &PostService{
 		repo:     repo,
 		ss:       ss,
 		notifier: notifier,
+		userRepo: userRepo,
 	}
 }
 
@@ -145,6 +147,15 @@ func (s *PostService) IsPostAccessible(userID uint, role string, postUserID uint
 	return userID == postUserID || model.HasMinRole(role, model.RoleModerator)
 }
 
+// CanCreatePost 检查用户是否可以创建帖子（LV0 用户不允许投稿）
+func (s *PostService) CanCreatePost(userID uint) bool {
+	user, err := s.userRepo.FindByID(userID)
+	if err != nil {
+		return false
+	}
+	return user.Exp >= 1
+}
+
 // RecordRead 记录已登录用户阅读文章（已登录去重 + 防刷冷却）
 func (s *PostService) RecordRead(userID, postID uint) {
 	firstRead, err := s.repo.RecordRead(userID, postID)

internal/service/repository.go

@@ -66,6 +66,11 @@ type postAdminStatStore interface {
 	CountPending() (int64, error)
 }
 
+// userExpReader PostService 读取用户经验值的最小接口（ISP）
+type userExpReader interface {
+	FindByID(id uint) (*model.User, error)
+}
+
 // postNotifier PostService 所需的通知服务接口
 type postNotifier interface {
 	NotifyPostApproved(userID uint, postTitle string, postID uint)