feat: 完善媒体管理与低内存环境稳定性

- 统一图片、视频和文件的上传策略，支持文件大小、格式和限流配置
- 新上传的图片、视频和文件默认保存到本地磁盘，并支持修改默认存储后端
- 图库、视频库和文件库新增搜索与批量删除功能
- 更新视频与文件 API 文档，并完善服务端扩展名和内容类型校验
- 完善备份恢复统计，分别展示媒体记录和存储对象进度
- 完善用户级清空存储流程，清理当前用户的媒体、任务和缓存
- 修复清空存储后最近任务残留以及媒体逻辑遗漏视频和文件的问题
- 增加站点同步异常恢复和超时兜底处理
- 缩略图 FFmpeg 限制为单线程并增加 10 秒超时保护
- 低内存服务器开启 HLS 转码时显示风险提示
- 完善 m3u8 临时合并文件的下载后、到期和启动时清理
- 更新中英文更新日志，并将版本号提升至 1.5.0

docs-site/en/guide/changelog.md

@@ -4,6 +4,28 @@ Version history and notable changes. The full log is also in the repo root [CHAN
 
 ---
 
+## [1.5.0] — 2026-10-17
+
+### Added
+
+- Search and batch deletion for the image, video, and file libraries
+- Unified upload policy for all media with configurable size, format, and rate limits
+- Default storage backend selection for newly uploaded images, videos, and files
+- High-risk storage clearing with typed confirmation, scoped to the current user
+- Low-memory warning when enabling HLS transcoding
+
+### Improved
+
+- Backup and restore progress now reports media records and storage objects separately
+- Video uploads are limited to complete container formats with server-side validation
+- Thumbnail FFmpeg processing is single-threaded and protected by a timeout
+- Temporary m3u8-to-MP4 files are cleaned after download, on expiry, and during startup
+
+### Fixed
+
+- Stale recent tasks after clearing storage and media logic that only covered images
+- Recovery fallback for interrupted site synchronization
+
 ## [1.4.4] — 2026-10-10
 
 ### Fixed