Close Задача №0 (SPEC §11) with the spec-sanctioned option (b): compare a
canonicalized ProseMirror form instead of raw bytes.
- canonicalize.ts: canonicalizeContent/docsCanonicallyEqual — strip node attrs.id,
drop null/undefined attrs, and drop attrs equal to their type's known non-null
schema default (KNOWN_DEFAULTS: link target/rel, comment.resolved, orderedList.start,
diagram/media align) so "absent" ≡ "default"; comment anchors + meaningful attrs kept
- roundtrip.ts: assert markdown byte-stability AND canonical stability; add --corpus
mode and mutually-exclusive-flag warning
- synthetic corpus (headings, marks, lists, table, callout, code w/ trailing \n,
diagrams, textStyle/mention) + canonicalize/corpus tests (558 green)
- known converter asymmetries (block image after paragraph; embed width/height
coercion) converge to a fixpoint after one export->import pass -> handled by
normalize-on-write at vault-write time; isolated under it.fails
- SPEC §11: record the resolution and normalize-on-write strategy
