二维码池批量上传与认证图片预览修复

- 后端新增批量创建二维码接口 POST /admin/chats/qrcodes/batch
- 前端二维码管理页支持多图拖拽批量上传
- 注册 qrcode 图片压缩场景(maxSide=2560, quality=0.95)
- 后端 normalizeScene 注册 qrcode scene
- 增强 AuthImage 组件支持 el-image 大图预览(previewSrcList)
- 修复 WithdrawalDetailDialog 提现凭证图片 401 问题
- 删除重复的 components/AuthImage.vue，统一使用共享组件
- 提交3剩余: 会话列表群类型图标、发布成功跳群、管理端路由等

backend/internal/modules/file/service.go

@@ -115,7 +115,7 @@ func fileURLForScene(scene string, key string) string {
 func normalizeScene(scene string) string {
 	scene = strings.TrimSpace(strings.ToLower(scene))
 	switch scene {
-	case "listing", "handoff", "dispute", "realname", "avatar", "home-banner", "chat", "payment-cert", "announcement":
+	case "listing", "handoff", "dispute", "realname", "avatar", "home-banner", "chat", "payment-cert", "announcement", "qrcode":
 		return scene
 	default:
 		return "misc"