fix: 已锁定文章禁止提交审核，隐藏提交按钮

- SubmitForAudit 新增 IsLocked 检查，锁定文章不可提交审核
- posts/show.html：已锁定文章不显示"提交审核"按钮

internal/service/post_service.go

@@ -251,6 +251,9 @@ func (s *PostService) SubmitForAudit(postID uint) error {
 	if err != nil {
 		return err
 	}
+	if post.IsLocked {
+		return common.ErrPostCannotEdit
+	}
 	if post.Status != model.PostStatusDraft && post.Status != model.PostStatusRejected {
 		return common.ErrPostCannotSubmit
 	}

templates/MetaLab-2026/html/posts/show.html

@@ -36,7 +36,7 @@
         {{if and $.Post (or (eq $.Post.UserID $.UID) $.CanAccessAdmin) (ne $.Post.Status "pending") (not $.Post.IsLocked)}}
         <a href="/studio/write?id={{$.Post.ID}}" class="btn btn-secondary">编辑</a>
         {{end}}
-        {{if and $.Post (eq $.Post.UserID $.UID) (or (eq $.Post.Status "draft") (eq $.Post.Status "rejected"))}}
+        {{if and $.Post (eq $.Post.UserID $.UID) (or (eq $.Post.Status "draft") (eq $.Post.Status "rejected")) (not $.Post.IsLocked)}}
         <button class="btn btn-primary" id="submitAuditBtn" data-id="{{$.Post.ID}}">提交审核</button>
         {{end}}
     </div>