sync from GitHub b534d37: feat: Improve model fetching efficiency and caching

sync from GitHub 29d4fb4: feat(client/backend): 请求级网络耗时遥测（客户端往返写进每条请求日志）；versionCode 415

sync from GitHub 00766f3: fix(client/backend): 常亮状态机重写（修复提前熄屏/自动重亮）；生图提示词优化链路修复与上下文增强；公式热路径不再重复下载；versionCode 403

sync from GitHub 583e33b: fix(tex): 公式渲染改用 MathJax+resvg 侧车；修复历史消息/后端重启后公式不渲染与端上缓存失效

sync from GitHub 1c15b7c: feat(tex-align): Implement formula rendering alignment tests and support for unwrapped formulas

sync from GitHub 943c198: feat(tex): 公式改用固定槽位模板（去掉 list-item 内的 for），ensure 失败带 HTTP 状态码

sync from GitHub f5e0fa0: latex render

sync from GitHub d5e6dd5: fix: 关闭图片修正时图片兼容化直传（修复"Failed to upload inline file."）+ 多图上传与图片管理；批量删除/回收站清理分批处理；versionCode 394

sync from GitHub 838c507: feat: add file transfer functionality with API and admin interface

sync from GitHub 49be50a: Refactor code structure for improved readability and maintainability

sync from GitHub ab63738: feat: 集成AI生图系统到后端

sync from GitHub a39d5b2: fix(client): 云端备份清空后本地索引失效自动转全量，修复增量复用死key导致blob_missing；versionCode 383

sync from GitHub c8523f8: feat(admin): one-click clear all V6 backups, merge backup panels, logs API

fix: 修复v6备份blob静默丢失 + 新增日志查询API key功能

sync from GitHub 1362c47: feat: update version code and enhance backup system

sync from GitHub 1c1ef96: feat: implement v6 backup storage layer with content-addressable blobs, snapshot management, and garbage collection

sync from GitHub efbc47a: fix: 容错非法 UTF-8 请求体，修复携带文件时 500

sync from GitHub af8fbe6: fix(后端): 下载端点放宽UA检查——修复request.download的403 no_client_t

sync from GitHub dad1933: fix(认证+恢复): 手表端长效token+refresh不吊销旧token+恢复容错

sync from GitHub 7b6cdc8: fix(v5后端): 修复管理面板加载不出数据-HF Space重建后从Hub恢复manifest

sync from GitHub 1477866: fix: blob_missing自动恢复 + 半屏修复 + 管理面板v5 + GC空目录

sync from GitHub 2f6e475: fix(backup-v5): create_set 返回 200 替代 201，修复小天才兼容性

sync from GitHub 4c1c300: feat(api): 添加 refresh 端点专用 token 验证，支持过期 token 刷新 feat(backup): 增加备份过程中的日志记录，优化并发处理 fix(user-account): 纯 JS 实现 base64url 解码，避免依赖 atob refactor: 更新应用版本至 2.4.0，修复多个潜在崩溃问题

sync from GitHub 511a971: fix(backup): /u/api/refresh 支持 GET 方法，修复 v5 备份上传崩溃

sync from GitHub 88ee0e8: fix(chat): 修复长消息正文渲染为空问题

sync from GitHub bf73005: refactor(backup): v5 云备份重构（方案C）+ token 刷新宽限期修复

sync from GitHub 4cf67db: refactor(backup): 重构云备份为 v5（方案 C：文件级 blob + manifest + ZIP 整包恢复）

sync from GitHub bcc7bb3: feat: 优化备份上传流程，增加 token 刷新和清理僵尸 session 的逻辑，提升用户体验 fix: 更新分段上传 session 的 TTL，避免内存占用过高

sync from GitHub e46d757: feat(music): 智能选段 top3 候选片段识别 + numpy 向量化能量计算

sync from GitHub 3bd068e: fix(music): 修复指纹污染+试听HTTPS+IP防护+音频增强

sync from GitHub e499291: feat(music): 新增识曲录音归档与排查面板

sync from GitHub ac31920: feat(music): 新增听歌识曲后端接口

sync from GitHub 6e39eaf: feat: 添加 latin1_safe_header 函数，确保 HTTP header 值的安全性，避免编码错误

sync from GitHub 8c7a6c8: feat: Enhance user backup and file management with session limits and token revocation

sync from GitHub 68bdec0: security: harden CORS, SSRF, brute-force, log injection and info leakage

sync from GitHub 197ca65: fix: 修复 seq 参数处理逻辑，确保合法值 0 不被误判为缺失；关闭生产环境自动文档端点以防泄露 API 结构

sync from GitHub 08a016f: fix: 全局加载日志通道开关，修复备份页日志丢失问题；改用 JSON body 上传备份片段，提升稳定性

sync from GitHub 1727379: feat: 备份分段上传，解决 2.6MB+ 大备份 OOM 崩溃

sync from GitHub 2c1b84a: feat: enhance TTS functionality and improve backup handling

sync from GitHub a191e47: fix(backend): 禁止 provider base_url 指向后端自身，从源头杜绝递归死循环

sync from GitHub 44f8976: fix(backend): 模型列表上游失败不再静默返回空，避免缓存毒化

sync from GitHub b7f5bb4: feat: AI消息长按支持收起为存档文件与放出覆盖，存档纳入云备份

sync from GitHub c6e6ba1: feat: 修复后端模型黑白名单配置

sync from GitHub 8910d41: Refactor TTS segment processing: implement segmented TTS pipeline with backend support for parallel generation and improved error handling

sync from GitHub 231252d: feat: 增加文件别名映射支持，优化备份下载与恢复流程

sync from GitHub 34a57e5: feat: add remote logging module for debugging and error tracking

sync from GitHub 0000529: feat: 优化云端备份下载与恢复流程，改用原生下载避免内存溢出，更新文件名格式

sync from GitHub b75e9bb: fix: 将备份下载超时时间从 30 秒缩短至 15 秒

sync from GitHub 9265007: feat: 加入 TTS 短时间缓存（前后端 5 分钟 TTL，启动清理避免堆积）

sync from GitHub 5c4665f: feat: Implement Hub to SQLite full sync functionality