Add a builtin _editor plugin that owns Markdown API/WebSocket sessions, canvas and modal UI, live refresh, tabs, prompt Extras for active-context open files, inline close confirmation, and Close All handling.
Route Markdown document artifacts to Editor while keeping Office/Desktop focused on LibreOffice formats, and update Desktop/Office prompts, menus, compatibility shims, and regression coverage.
Add read/edit support for Office document artifacts, including direct DOCX, XLSX, and PPTX updates with version history preservation. Inject compact active canvas metadata so agents can discover opened files without loading file contents. Move detailed usage guidance into the office-artifacts skill and keep the always-on tool prompt lean to avoid context bloat.
