Expand the dedicated Editor surface with safe rendered preview mode, ACE-backed source editing, browser-style tabs, toolbar/file actions, preview search, and richer Markdown rendering for code blocks, task lists, images, tables, math, local links, and footnotes.
Keep open Markdown files synchronized with the active context and saved tool edits, including live refresh for document_artifact and text_editor results without routing Markdown through Desktop/Office.
Add inline preview-page editing, clickable preview task-list checkboxes, source editor rehydration after preview-mode refreshes, and regression coverage for the new editor wiring and sync behavior.
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.
