备份策略改为部署前手动快照：部署合同增加手动快照模式 [08-28-production-arm-backup-transfer-incident]

- 用户决定仅用部署前手动轻量快照，不再推进对象存储、ARM/hyinda-20c 备份
- refresh-deployment-contract 新增 /etc/hyb-oa-backup-mode 显式模式：
  无文件保持原自动模式；manual_snapshot 要求三个备份 timer 停用且备份
  service 已退出，ops timer 仍须运行；内容/属主/符号链接异常 fail-closed
- probe 部署前与 refresh 部署后均校验模式与 timer/service 一致性
- 新增 44 backup_mode_invalid / 45 backup_timer_not_disabled 分类及合同测试
- 记录 10-05 ARM 与 hyinda-20c 只读核验结果、远端切换顺序与回滚
- 远端切换未执行，需另行批准

Co-Authored-By: Claude Opus 5.5 <[email protected]>

.trellis/tasks/08-28-production-arm-backup-transfer-incident/task.json

@@ -12,7 +12,7 @@
   "assignee": "shunli",
   "createdAt": "2026-08-28",
   "completedAt": null,
-  "branch": null,
+  "branch": "main",
   "base_branch": "main",
   "worktree_path": null,
   "commit": null,