mdrt-2 (markdown export): add lossless turndown rules for the custom nodes
that had no rule — transclusionReference, pageBreak, mention, status. Each
re-emits the node as inert raw HTML carrying every data-* attribute instead
of being silently dropped (childless atom divs) or collapsed to bare text
(mention/status losing data-id/data-color). Empty atom blocks are made
non-blank before turndown's blank-rule strips them (mirrors the footnote-ref
fix). markdownToHtml passes the raw HTML through and each node's parseHTML
rebuilds it, so the form round-trips. Flips the it.fails cases to passing and
adds export + import round-trip coverage.
persist-6 (collab store): add a store-side empty-guard in onStoreDocument.
Before updatePage, if the serialized live doc is an empty paragraph doc AND
the persisted page is non-empty, skip the write and log — unless an explicit
context.intentionalClear signal is present (deliberate select-all+delete).
New/empty pages and unchanged docs are unaffected. Flips the it.failing case
to passing and adds escape-hatch + empty-over-empty coverage.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
78953cf775