feat: 书库导入导出/图片变体/书籍搜索/小组件运行时等

新增：
- 书库导入导出（library_import/library_export）及测试
- 图片变体生成（image_variants）与响应式图片（responsiveImage）
- 书籍搜索（bookSearch）+ BookSearch/LibrarySearchGrid 组件
- 小组件运行时（widgetRuntime）与静态检查（widgetLint）
- 上传缓存中间件（upload_cache）与字体 CSS 提取脚本

其它：
- 后端 handlers/services 全量调整
- 前端页面、组件、库函数与配置更新

backend/service/comment.go

@@ -44,7 +44,7 @@ func IsNecroReply(lastReplyAt time.Time, afterHours int, now time.Time) bool {
 
 // CommentService 评论服务
 type CommentService struct {
-	db *gorm.DB
+	db      *gorm.DB
 	setting *SettingService
 }
 
@@ -297,6 +297,80 @@ func (s *CommentService) FloorNumber(postID, commentID uint) int {
 	return FloorNumber(s.db, postID, commentID)
 }
 
+// CommentAnchor 评论在所属帖子内的相对锚点：
+// Floor=楼层号（含软删/待审占位，口径同 FloorNumber）；IsRoot=true 为主楼，
+// false 为楼中楼（锚点需附带评论 ID 才能精确定位具体回复）。
+type CommentAnchor struct {
+	Floor  uint `json:"floor"`
+	IsRoot bool `json:"is_root"`
+}
+
+// CommentAnchors 批量查询评论锚点（两条 SQL，避免逐行 N+1）；
+// 评论或其主楼已不存在（如整串被彻底删除）时不出现在结果中。
+func CommentAnchors(db *gorm.DB, ids []uint) map[uint]CommentAnchor {
+	out := make(map[uint]CommentAnchor, len(ids))
+	if db == nil || len(ids) == 0 {
+		return out
+	}
+	// Unscoped：软删/待审评论仍占楼层，与 FloorNumber 同口径
+	var targets []model.Comment
+	if err := db.Unscoped().
+		Select("id", "post_id", "parent_id", "root_id", "created_at").
+		Where("id IN ?", ids).Find(&targets).Error; err != nil {
+		return out
+	}
+	rootIDSet := make(map[uint]struct{}, len(targets))
+	for _, c := range targets {
+		rid := c.ID
+		if c.ParentID != nil && c.RootID != nil {
+			rid = *c.RootID
+		}
+		rootIDSet[rid] = struct{}{}
+	}
+	rootIDs := make([]uint, 0, len(rootIDSet))
+	for rid := range rootIDSet {
+		rootIDs = append(rootIDs, rid)
+	}
+	// 每个主楼之前（按 created_at/id 升序）的主楼数即楼层号 - 1
+	type aheadRow struct {
+		RootID uint
+		Ahead  int64
+	}
+	var aheadRows []aheadRow
+	if err := db.Unscoped().Table("comments AS f").
+		Select(`f.id AS root_id,
+			(SELECT COUNT(*) FROM comments c
+			 WHERE c.post_id = f.post_id AND c.parent_id IS NULL
+			   AND (c.created_at < f.created_at
+			        OR (c.created_at = f.created_at AND c.id < f.id))) AS ahead`).
+		Where("f.id IN ? AND f.parent_id IS NULL", rootIDs).
+		Scan(&aheadRows).Error; err != nil {
+		return out
+	}
+	floorByRoot := make(map[uint]uint, len(aheadRows))
+	for _, r := range aheadRows {
+		floorByRoot[r.RootID] = uint(r.Ahead) + 1
+	}
+	for _, c := range targets {
+		isRoot := c.ParentID == nil
+		rid := c.ID
+		if !isRoot && c.RootID != nil {
+			rid = *c.RootID
+		}
+		floor := floorByRoot[rid]
+		if floor == 0 {
+			continue
+		}
+		out[c.ID] = CommentAnchor{Floor: floor, IsRoot: isRoot}
+	}
+	return out
+}
+
+// AnchorsByCommentIDs 见包级 CommentAnchors
+func (s *CommentService) AnchorsByCommentIDs(ids []uint) map[uint]CommentAnchor {
+	return CommentAnchors(s.db, ids)
+}
+
 // applyCommentListVisibility 评论流可见性：published，或 pending 且（作者 / 该板可审）；
 // 软删行：已发布的对所有人占位；待审软删仅作者/可审者可见占位。
 func applyCommentListVisibility(db *gorm.DB, boardID, viewerID uint, actor *Actor) *gorm.DB {
@@ -442,6 +516,8 @@ type UserCommentItem struct {
 	PostID    uint      `json:"post_id"`
 	PostTitle string    `json:"post_title"`
 	Content   string    `json:"content"`
+	Floor     uint      `json:"floor"`   // 所属楼层相对序号（主楼为自身楼层）
+	IsRoot    bool      `json:"is_root"` // 主楼/楼中楼，供前端拼 #comment-{floor}[-r{id}]
 	CreatedAt time.Time `json:"created_at"`
 }
 
@@ -470,6 +546,17 @@ func (s *CommentService) ListByUser(userID uint, page, size int) ([]UserCommentI
 	if items == nil {
 		items = []UserCommentItem{}
 	}
+	ids := make([]uint, 0, len(items))
+	for _, it := range items {
+		ids = append(ids, it.ID)
+	}
+	anchors := s.AnchorsByCommentIDs(ids)
+	for i := range items {
+		if a, ok := anchors[items[i].ID]; ok {
+			items[i].Floor = a.Floor
+			items[i].IsRoot = a.IsRoot
+		}
+	}
 	return items, total, nil
 }