unarchive

Restore archived sessions in the DeepSeek Harness: /unarchive command + unarchive_session tool (profile bundle)

把社区里零散的会话能力收成一套：归档目录、恢复原位、删除、编辑重发。补官方缺口，走公开 slot，不打核心补丁。A session pack for DeepSeek Harness: archive directory, restore, delete, edit-and-resend. One place for features that usually live in separate plugins.