v0.12.0-beta.0

Delta since previous beta (v0.11.1-beta.5) — 1 new changeset.

Minor Changes

• feat(markdown): end-to-end byte fidelity — markdown round-trips byte-exact, agents' untouched bytes survive concurrent edits

  The markdown engine no longer canonicalizes source formatting on the WYSIWYG/cross-surface edit path. Every producer-fixable byte-residual axis now round-trips byte-exact through serialize(parse(x)): table outer pipes, delimiter-row dashes and alignment padding, ordered-list numbering (1. 1. 1. stays), list marker spacing and continuation indents, fence length and info-string padding, strikethrough delimiter (~ vs ~~), task-checkbox case, wiki-link inner padding, opaque-extension embeds (![[notes.foo]] no longer downcasts to a plain link), inline math ($x$ stays $x$ instead of rewriting to $$x$$, with currency safety preserved), doc-start --- thematic breaks (no longer rewritten to ***, and a doc-start --- no longer corrupts adjacent blocks), BOM, leading/trailing blank lines, inter-block blank-line counts, and tab-indented code. One visible consequence: a literal frontmatter-shaped block (---/key: val/---) ingested directly into the parse engine now renders as visible markdown (thematic break + setext heading) instead of being silently dropped.

  Silent data-loss fixes: boundary-whitespace emphasis (<em>foo </em>) now serializes to a re-parseable form instead of degrading to plain text; entity references in a fenced-code info string survive instead of being stripped; [link](</my uri>) parses as a link instead of literal text; inline code containing | inside a table cell keeps its escape instead of corrupting the table. The serializer also stops escaping bare */_/~ and line-start = where CommonMark does not require it.

  Agent find-fidelity (PRD-6654): a concurrent human WYSIWYG edit no longer rewrites an agent's untouched blocks in Y.Text — the map-driven Observer A splice is now the default path and a parse-equivalent row-no-trailing-pipe divergence no longer forces a canonicalizing write-back — so exact-match find-and-replace on previously written content keeps succeeding.

  Clipboard/export rendering: img/video/audio compat components render as real HTML elements instead of placeholders, and entity references and <> destinations in link/image URLs and titles decode correctly (with URL sanitization preserved).