dsh-classic-coding: Opening the Monaco Editor and File Tree in the DSH Web UI

`dsh-classic-coding` is a DSH client plugin maintained by `better-er`, designed to solve the problem of frequently switching to external editors during conversational development. It provides a side overlay panel in the DSH Web UI, integrating a file tree and Monaco editor, allowing users to view, edit, and save workspace files directly without leaving the current session. Core features include: the "Classic Coding" button at the bottom of the sidebar triggers the panel; the left file tree supports lazy loading and filtering of unrelated directories; the Monaco editor supports multiple tabs, syntax highlighting, and `Ctrl+S` to save; the bottom status bar displays the path and save feedback. The panel supports closing via `Esc` or clicking the mask, and automatically adapts to light and dark themes. Additionally, file entries in the message stream can be opened directly within this panel. Installation is done via `