dsh-ssh-bridge: Local SSH Bridge Plugin

`dsh-ssh-bridge` is a local SSH bridge plugin for DeepSeek Harness (DSH), designed to securely execute remote commands. The plugin allows users to enter a password via a browser interface to establish an encrypted channel, while the Agent operates remote hosts by invoking tools (such as `router_exec`) through a local API. It supports standalone operation, automatic port fallback, and random token authentication, with the password remaining solely in process memory throughout, thereby ensuring both the security and flexibility of the connection.