Code Mode for DeepSeek Harness

The DeepSeek Harness (DSH) Code mode plugin embeds a terminal in the web interface, allowing users to run `dsh --profile omdsh-tui` directly. Core features include displaying a real terminal in the conversation column, syncing session state in the sidebar, supporting new sessions, and updating names via the OSC 0 mechanism. The plugin does not modify core logic; instead, it forwards byte streams. After disconnection, the terminal process enters a grace period waiting for reconnection. It requires Node.js `^22.19.0 || >=24.0.0` and is MIT licensed.