feat: 定时发布系统 — Phase 5 完成

- Post ScheduledAt 字段
- Scheduler goroutine 每分钟扫描到期文章
- Create/Update 校验最短 30min 定时
- Approve 审核晚于定时则即时发布
- public 列表+空间页过滤未到期文章
- 写文章页 datetime-local 选择器（min=now+30min）
- AutoMigrate 追加新表

internal/controller/interfaces.go

@@ -42,9 +42,9 @@ type postUseCase interface {
 
 // studioUseCase StudioController 对 PostService 的最小依赖（ISP：9 个方法）
 type studioUseCase interface {
-	Create(userID uint, title, body, visibility, postType, reprintSource, declaration string, reprintProhibited bool, categoryID string) (*model.Post, error)
+	Create(userID uint, title, body, visibility, postType, reprintSource, declaration string, reprintProhibited bool, categoryID, scheduledAt string) (*model.Post, error)
 	GetByID(id uint) (*model.Post, error)
-	Update(postID uint, title, body, visibility, postType, reprintSource, declaration string, reprintProhibited bool, categoryID string) error
+	Update(postID uint, title, body, visibility, postType, reprintSource, declaration string, reprintProhibited bool, categoryID, scheduledAt string) error
 	Delete(postID uint) error
 	SubmitForAudit(postID uint) error
 	ListByUser(userID uint, status string, page, pageSize int) ([]model.Post, int64, error)

internal/controller/studio_post_api_controller.go

@@ -30,8 +30,12 @@ func (ctrl *StudioController) Create(c *gin.Context) {
 		return
 	}
 
-	post, err := ctrl.postService.Create(uid, req.Title, req.Body, req.Visibility, req.PostType, req.ReprintSource, req.Declaration, req.ReprintProhibited, req.CategoryID)
+	post, err := ctrl.postService.Create(uid, req.Title, req.Body, req.Visibility, req.PostType, req.ReprintSource, req.Declaration, req.ReprintProhibited, req.CategoryID, req.ScheduledAt)
 	if err != nil {
+		if err == common.ErrScheduledTooSoon {
+			common.Error(c, http.StatusBadRequest, err.Error())
+			return
+		}
 		common.Error(c, http.StatusInternalServerError, "发布失败")
 		return
 	}
@@ -74,7 +78,7 @@ func (ctrl *StudioController) Update(c *gin.Context) {
 		return
 	}
 
-	if err := ctrl.postService.Update(uint(id), req.Title, req.Body, req.Visibility, req.PostType, req.ReprintSource, req.Declaration, req.ReprintProhibited, req.CategoryID); err != nil {
+	if err := ctrl.postService.Update(uint(id), req.Title, req.Body, req.Visibility, req.PostType, req.ReprintSource, req.Declaration, req.ReprintProhibited, req.CategoryID, req.ScheduledAt); err != nil {
 		common.Error(c, http.StatusInternalServerError, "编辑失败")
 		return
 	}