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/handler/chat.go

@@ -4,6 +4,7 @@ import (
 	"errors"
 	"net/http"
 	"strconv"
+	"time"
 
 	"github.com/freefire/jiang13-bbs/middleware"
 	"github.com/freefire/jiang13-bbs/model"
@@ -42,6 +43,26 @@ func chatRoomID(c *gin.Context) (uint, bool) {
 	return uint(id), true
 }
 
+// formatMuteDurationCN 禁言时长中文格式化，供系统提示消息使用
+func formatMuteDurationCN(minutes int) string {
+	switch {
+	case minutes >= 30*24*60:
+		return "30 天"
+	case minutes >= 7*24*60:
+		return "7 天"
+	case minutes >= 3*24*60:
+		return "3 天"
+	case minutes >= 24*60:
+		return "1 天"
+	case minutes >= 12*60:
+		return "12 小时"
+	case minutes >= 60:
+		return "1 小时"
+	default:
+		return strconv.Itoa(minutes) + " 分钟"
+	}
+}
+
 func (h *Handlers) chatOversee(userID uint) bool {
 	actor, err := h.Auth.LoadActor(userID)
 	if err != nil || actor == nil {
@@ -322,7 +343,7 @@ func (h *Handlers) KickChatMember(c *gin.Context) {
 	c.JSON(http.StatusOK, gin.H{"ok": true})
 }
 
-// SetChatMemberMute 禁言/解禁成员
+// SetChatMemberMute 禁言/解禁成员；duration_minutes 可选：0/缺省=永久，>0=指定分钟数
 func (h *Handlers) SetChatMemberMute(c *gin.Context) {
 	claims := middleware.CurrentUser(c)
 	roomID, ok := chatRoomID(c)
@@ -335,17 +356,59 @@ func (h *Handlers) SetChatMemberMute(c *gin.Context) {
 		return
 	}
 	var body struct {
-		Muted bool `json:"muted"`
+		Muted           bool `json:"muted"`
+		DurationMinutes int  `json:"duration_minutes"`
 	}
 	if err := c.ShouldBindJSON(&body); err != nil {
 		c.JSON(http.StatusBadRequest, gin.H{"error": "请求参数无效"})
 		return
 	}
-	if err := h.Chat.SetMemberMute(claims.ID, roomID, uint(targetID), body.Muted, h.chatOversee(claims.ID)); err != nil {
+	duration := time.Duration(body.DurationMinutes) * time.Minute
+	targetName, err := h.Chat.SetMemberMute(claims.ID, roomID, uint(targetID), body.Muted, duration, h.chatOversee(claims.ID))
+	if err != nil {
 		c.JSON(chatErrToStatus(err), gin.H{"error": err.Error()})
 		return
 	}
-	c.JSON(http.StatusOK, gin.H{"ok": true, "muted": body.Muted})
+	// 向房间内广播禁言/解禁事件，客户端据此更新输入框状态与成员列表
+	var mutedUntil *time.Time
+	if body.Muted && body.DurationMinutes > 0 {
+		t := time.Now().Add(duration)
+		mutedUntil = &t
+	}
+	// 落库一条系统提示消息，刷新后仍可见（走 SendSystemMessage 统一处理房间 last_message_id 等）
+	var sysContent string
+	if body.Muted {
+		if body.DurationMinutes > 0 {
+			sysContent = targetName + " 已被禁言 " + formatMuteDurationCN(body.DurationMinutes)
+		} else {
+			sysContent = targetName + " 已被禁言 永久"
+		}
+	} else {
+		sysContent = targetName + " 的禁言已被解除"
+	}
+	sysMsg, _ := h.Chat.SendSystemMessage(roomID, sysContent)
+	// 广播系统消息到房间（sender_id=0，前端按系统消息渲染）
+	if sysMsg != nil && sysMsg.ID > 0 {
+		h.Hub.BroadcastRoom(realtime.RoomChat(roomID), realtime.Envelope{
+			Type: realtime.EventChatMessage,
+			Data: gin.H{
+				"message": sysMsg,
+			},
+		})
+	}
+	h.Hub.BroadcastRoom(realtime.RoomChat(roomID), realtime.Envelope{
+		Type: realtime.EventChatMemberMuted,
+		Data: gin.H{
+			"room_id":         roomID,
+			"user_id":         uint(targetID),
+			"muted":           body.Muted,
+			"muted_until":     mutedUntil,
+			"duration_minutes": body.DurationMinutes,
+			"target_name":     targetName,
+			"operator_id":     claims.ID,
+		},
+	})
+	c.JSON(http.StatusOK, gin.H{"ok": true, "muted": body.Muted, "duration_minutes": body.DurationMinutes})
 }
 
 // SetChatMemberRole 站长任命/撤销群管理员