dsh-tool-terminal-search: Search in Terminal Backtrack

dsh-tool-terminal-search is a terminal log search plugin for DeepSeek Harness (dsh), designed to address the difficulty of reading massive logs via pagination. Built on the `ctx.terminals.read` interface, it allows the model to directly search retained scrollback buffers using substring or regular-expression queries. After installation, the dsh configuration must be restarted so the model can access this tool. It supports literal matching or regular-expression matching, returns matched line content and offsets, and includes a regular-expression caching mechanism to improve performance. This plugin depends on the dsh 0.1.2-alpha.5 release line.