DSH-Codinput: Upgrading the DeepSeek Harness Input Box to an Editor-Style Panel

The DSH-Codinput plugin for DeepSeek Harness (DSH), built on CodeMirror 6, replaces the chat input box with an editor-style panel to address interaction limitations of traditional input fields in scenarios such as Markdown and code indentation. It provides a three-state single-instance mode (normal, floating, and sidebar), supporting split editing and preview, undo history retention, and `/` and `@` trigger pipelines. It also supports attachments, synchronized voice input, and performance monitoring, while replicating the official permission and model access mechanisms. Users can install it with a single command, switch modes by dragging or using the sidebar, and quit by entering `/codinput` in the sidebar.