epic(docs): Markdown and MDX linting and tooling #859

What this is. One place for the problems with how the repo lints and formats Markdown and MDX. #499 and #525 were split out of the CI epic #740.

On hold. The Markdown linting setup is being reworked as a whole, so these may be superseded rather than fixed one at a time. Check with @EricAndrechek before starting one.

Issues

• docs: enforce and fix Markdown/MDX style properly — markdownlint can't parse MDX #499: markdownlint can't parse MDX, so .mdx pages aren't style-checked properly, and WH002's fence check under-reports.
• lint(WH001): four-space-indented lines are skipped, so hard-wrapped nested list items are never reported or fixed #525: WH001 skips four-space-indented lines, so hard-wrapped nested list items are never reported or fixed.
• fix(agents): markdown-on-save treats a nested worktree's CHANGELOG.md as docs prose #795: the markdown-on-save hook treats a nested worktree's CHANGELOG.md as docs prose.

Open pull request

• fix(lint): parse Markdown and MDX in WH001/WH002, autofix .mdx prose #760 makes WH001 and WH002 read a real Markdown/MDX parse, which addresses lint(WH001): four-space-indented lines are skipped, so hard-wrapped nested list items are never reported or fixed #525 and docs: enforce and fix Markdown/MDX style properly — markdownlint can't parse MDX #499's first and third options.