DeepSeek Harness Long-Text Input Plugin

`dsh-longtext-input` is a plugin for DeepSeek Harness that solves the issue of bloated conversation flows caused by pasting extremely long text. It saves long content to a `.dsh-longtext` folder in the workspace, leaving only an `@` reference in the input box to keep the interface clean. It supports automatic filename generation, frosted-glass appearance adaptation, and keyboard shortcuts, and allows users to manually instruct the model to read the file contents. Installation requires restarting the application. Note that for locally checked-out installations, the directory must not be moved or deleted.