fix: 修复帖子提交审核权限缺失 + 防重复提交 + 分页逻辑复用

- 修复 Submit API 缺少 uid 权限检查，任意登录用户可提交他人帖子审核
- 前端 handleSubmit 添加 submitting 锁和按钮禁用/恢复，防止重复提交
- 分页计算 TotalPages/PrevPage/NextPage 提取为 Pagination 方法，消除三处重复代码

internal/controller/post_controller.go

@@ -49,11 +49,7 @@ func (ctrl *PostController) ListPage(c *gin.Context) {
 
 	p := common.Pagination{Page: page, PageSize: pageSize}
 	p.DefaultPagination()
-	totalPages := int((total + int64(p.PageSize) - 1) / int64(p.PageSize))
-	prevPage := p.Page - 1
-	if prevPage < 1 { prevPage = 1 }
-	nextPage := p.Page + 1
-	if nextPage > totalPages { nextPage = totalPages }
+	totalPages := p.TotalPages(total)
 
 	c.HTML(http.StatusOK, "posts/index.html", common.BuildPageData(c, gin.H{
 		"Title":      "社区帖子",
@@ -61,8 +57,8 @@ func (ctrl *PostController) ListPage(c *gin.Context) {
 		"Total":      total,
 		"Page":       p.Page,
 		"TotalPages": totalPages,
-		"PrevPage":   prevPage,
-		"NextPage":   nextPage,
+		"PrevPage":   p.PrevPage(),
+		"NextPage":   p.NextPage(totalPages),
 		"Keyword":    keyword,
 		"ExtraCSS":   "/static/css/posts.css",
 	}))
@@ -276,12 +272,30 @@ func (ctrl *PostController) Delete(c *gin.Context) {
 
 // Submit API 提交审核
 func (ctrl *PostController) Submit(c *gin.Context) {
+	uidObj, _ := c.Get("uid")
+	uid, ok := uidObj.(uint)
+	if !ok {
+		common.Error(c, http.StatusUnauthorized, "请先登录")
+		return
+	}
+
 	id, err := strconv.ParseUint(c.Param("id"), 10, 64)
 	if err != nil {
 		common.Error(c, http.StatusBadRequest, "无效的帖子 ID")
 		return
 	}
 
+	// 权限检查：仅帖子作者可提交审核
+	post, err := ctrl.postService.GetByID(uint(id))
+	if err != nil {
+		common.Error(c, http.StatusNotFound, "帖子不存在")
+		return
+	}
+	if post.UserID != uid {
+		common.Error(c, http.StatusForbidden, "无权操作此帖子")
+		return
+	}
+
 	if err := ctrl.postService.SubmitForAudit(uint(id)); err != nil {
 		if errors.Is(err, common.ErrPostCannotSubmit) || errors.Is(err, common.ErrPostNotFound) {
 			common.Error(c, http.StatusBadRequest, err.Error())
@@ -312,13 +326,12 @@ func (ctrl *PostController) ListAPI(c *gin.Context) {
 
 	p := common.Pagination{Page: page, PageSize: pageSize}
 	p.DefaultPagination()
-	totalPages := int((total + int64(p.PageSize) - 1) / int64(p.PageSize))
 
 	common.Ok(c, model.PostListResult{
 		Items:      posts,
 		Total:      total,
 		Page:       p.Page,
-		TotalPages: totalPages,
+		TotalPages: p.TotalPages(total),
 	})
 }