- edit_diagram applies nothing when any operation fails, rejects invalid or
multi-cell new_xml, validates only the target page, and returns the
current page XML on every rejection (including stale edits)
- Fix get_diagram reading the old diagram right after an AI write: the
preview pushed its sync reply with a newer version than it was taken at
- Keep a user edit that loses the race with an AI write in history and
tell the user in the preview
- Autofix removes only exact foreign tags (a stray <mxGraph/> deleted
<mxGraphModel>), fixes tag case, drops orphan <mxPoint>s, and rejects
unknown element names in model XML
- Edit empty and compressed pages; PNG exports use the page on screen;
tag download exports; reload from the server after a page export
- Expand ~ in paths, tell the model when the browser sync timed out,
use registerPrompt, require SDK ^1.31.0
