session-fork 2

Unified DSH checkpoints: session + workspace + config three-state snapshots with one-shot rollback — /checkpoint and /rewind commands, a checkpoint tool, automatic interval snapshots, a Settings page timeline with pairwise diffs, and seed-replay session r

Trae-style withdraw for DeepSeek Harness Web: a rollback button on every user/assistant message that restores the workspace code (git commits or hard-link file snapshots) and forks the session back to the last completed turn. 会话撤回插件：每条消息一键回滚代码与对话。