Persist a user-edited document (non-AI autosave).

Persist a HUMAN-edited document — the editor's debounced autosave + save-on-blur — WITHOUT an AI turn. Re-indexes the html into the target document (preserving its durable identity so it UPDATES the same Files entry), then saves it so pure typing is preserved AND other sessions with the same document open stay in sync. The AI-edit flow is unaffected (autosave saves first; a later AI result is merged with your saved edits). Non-billable, REST-only (a UI affordance, not an MCP tool).