升级帖子编辑与 Feed 体验：TipTap 富文本、修订历史、排序与编辑时限。

将 Markdown 编辑器替换为 TipTap WYSIWYG，新增帖子修订记录与 diff 展示；首页支持最新/回复排序与本地缓存；后台可配置编辑时限与锁定帖子；侧边栏整合板块导航并优化 Feed 布局。

Co-authored-by: Cursor <cursoragent@cursor.com>

service/settings.go

@@ -0,0 +1,70 @@
+package service
+
+import (
+	"strconv"
+	"sync"
+
+	"git.iioio.com/freefire/jiang13-forum/model"
+)
+
+const (
+	SettingPostEditWindowHours = "post_edit_window_hours"
+	defaultEditWindowHours     = 24
+)
+
+// ForumSettingsService 论坛全局设置
+type ForumSettingsService struct {
+	mu sync.RWMutex
+}
+
+func NewForumSettingsService() *ForumSettingsService {
+	s := &ForumSettingsService{}
+	s.ensureDefaults()
+	return s
+}
+
+func (s *ForumSettingsService) ensureDefaults() {
+	var count int64
+	model.DB.Model(&model.ForumSetting{}).Where("`key` = ?", SettingPostEditWindowHours).Count(&count)
+	if count == 0 {
+		model.DB.Create(&model.ForumSetting{
+			Key:   SettingPostEditWindowHours,
+			Value: strconv.Itoa(defaultEditWindowHours),
+		})
+	}
+}
+
+// PostEditWindowHours 返回用户可编辑帖子的时限（小时），0 表示不限
+func (s *ForumSettingsService) PostEditWindowHours() int {
+	s.mu.RLock()
+	defer s.mu.RUnlock()
+	var setting model.ForumSetting
+	if err := model.DB.First(&setting, "`key` = ?", SettingPostEditWindowHours).Error; err != nil {
+		return defaultEditWindowHours
+	}
+	h, err := strconv.Atoi(setting.Value)
+	if err != nil || h < 0 {
+		return defaultEditWindowHours
+	}
+	return h
+}
+
+// SetPostEditWindowHours 设置编辑时限（小时），0 表示不限
+func (s *ForumSettingsService) SetPostEditWindowHours(hours int) error {
+	if hours < 0 {
+		return ErrInvalidSetting
+	}
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	return model.DB.Save(&model.ForumSetting{
+		Key:   SettingPostEditWindowHours,
+		Value: strconv.Itoa(hours),
+	}).Error
+}
+
+// ForumSettings 返回所有可配置的论坛设置
+func (s *ForumSettingsService) ForumSettings() map[string]int {
+	return map[string]int{
+		"post_edit_window_hours": s.PostEditWindowHours(),
+	}
+}