Editor Protocol Matrix Completion

Goal

Push docs/editor-behavior/editor-protocol-matrix.md from broad family coverage to near-exhaustive markdown/Typora protocol coverage for the still-missing rows:

• paragraph expanded-selection variants
• heading selection variants
• deeper blockquote variants
• fuller code-block variants
• more table anchor/focus and boundary escalation rows
• mention/date movement variants
• TOC non-delete keyboard behavior
• columns per-key behavior
• explicit evidence mapping for every remaining seeded or partial row in the in-scope markdown/Typora lane

Constraints

• keep markdown-editing-spec.md readable; do not dump exhaustive rows there
• keep markdown-parity-matrix.md as the release gate, not the protocol doc
• follow docs/editor-behavior/markdown-standards.md authority order
• treat toggle, comment, suggestion, discussion, and yjs as deferred

Findings

• docs/solutions/patterns/critical-patterns.md does not exist here, so the learnings pass has to rely on targeted solution docs instead of that global file.
• Existing solution docs already lock two key laws we must not contradict:
  • markdown containers lift one level at a time
  • table selection must own keydown before native selection flashes
• The current protocol matrix already covers a lot of family breadth, but too many rows still stop at seeded or partial.
• The missing work is mostly row expansion plus evidence mapping, not new code.

Phases

1. gather missing scenario families and supporting tests
2. expand the protocol matrix with the requested rows
3. map every touched row to current evidence or mark the true gap
4. sync spec/readme only if the doc split drifted
5. verify docs formatting and report the honest remaining gap

Progress

• 2026-04-03: started learnings pass and current-doc audit
• 2026-04-03: expanded editor-protocol-matrix.md for paragraph selections, heading selections, deeper blockquote and code-block rows, table boundary and anchor/focus cases, mention/date movement, TOC non-delete keys, and column per-key behavior
• 2026-04-03: tightened row-level evidence so touched specified and partial rows point at real tests or explicit missing targeted regressions
• 2026-04-03: updated README.md so the protocol file is described as the row-level matrix instead of just a backlog
• 2026-04-03: pnpm lint:fix passed after the doc expansion
• 2026-04-03: added real tests for markdown-native paragraph, heading, blockquote, list, code-block, and table protocol rows that were still only partial or specified
• 2026-04-03: fixed real behavior gaps for same-block heading selection ↵, table second selectAll, first-line code-block ⌫, empty inner code-line ⌫, and multiblock quoted ⇤
• 2026-04-03: closed the remaining block-editor-native protocol rows for mention, date, TOC, and columns with targeted tests; mention arrow movement now treats mentions as atomic steps
• 2026-04-03: expanded the protocol matrix to cover task-list, strikethrough, and math rows instead of leaving tables as the only markdown-extension protocol family
• 2026-04-03: closed the remaining styling/layout protocol rows by locking textIndent and broader indent ownership with direct tests
• 2026-04-03: external standards pass confirmed the current UX north stars and added one missing authority: GitHub for GFM-only constructs; math authority is now stated as LaTeX / KaTeX-style conventions instead of hiding behind implementation-library names
• 2026-04-03: reopened autolink literal and footnote as the remaining explicit blockers to a literal "100% CommonMark + GFM extensions" claim
• 2026-04-03: closed autolink literal with package-surface coverage and fixed markdown serialization to emit bare URL markdown instead of degrading to bracket-link form
• 2026-04-03: upgraded footnote fallback from silent data loss to explicit plain-text preservation of references and definitions, then locked that fallback in package and app tests
• 2026-04-03: adversarial external rescan did not surface a stronger generic WYSIWYG authority than Typora / Google Docs / Notion / Milkdown, but it did confirm GitHub should stay explicit for GFM-only constructs and pushed table structure ops into the protocol matrix
• 2026-04-03: created an explicit deferred integration red suite under apps/www/src/__tests__/package-integration/__deferred__/ for the remaining interaction classes outside the current content-editing claim: clipboard, IME/composition, mouse drag/selection, and platform shortcuts