Known-good live state before the pricing page F2 redesign

Known-good rollback point before any mock-to-live page build-out. Inc…

…ludes: sitewide footer, consent fixes, newsletter consent-sync, Google white-label, CF Web Analytics, nudge timing, and the finalized brand-forward v3 design mocks (design only, not yet live pages).

Pre-layout-v2 checkpoint.

Site state captured before the layout migration to blog-page-mock-v2:
- Phase 0-3 + Phase 5 shipped end-to-end
- Exercise audit: 1894/2068 (91.6%) matching after 4 passes + LLM repair
- Nav dropdown hover bridges + warning-strip grader hardening live
- Bootstrap-style 1170px-max layout still in place

Revert path:  git checkout checkpoint-2026-05-29-pre-layout-v2 -- .

Remove white border on output box

Bootstrap's `pre` default border (1px solid #ccc) was leaking onto
.webr-output, showing a thin light-gray line on the left, right, and
bottom edges. Set `border: 0 none` (plus `border-radius: 0`) and keep
the dark slate `border-top` as the divider from the editor.

Replace CodeMirror with vanilla textarea swap

Removes the ~200KB CodeMirror bundle. On first click/focus/keystroke,
the static Pygments-rendered div is replaced with a plain textarea
carrying the same code. Caret position is preserved from the click
point via caretPositionFromPoint.

Run button reads textarea.value when hydrated, else textContent.
Copy + Reset updated similarly. Ctrl+Enter runs, Tab indents two
spaces, Escape blurs.

Vendored codemirror-5.65.16.min.{js,css} deleted. VENDOR_ASSETS in
build.py cleared. Template no longer emits cm-js-href/cm-css-href
meta tags.

Known regression: syntax colors and line numbers disappear on click
(to be addressed by CodeJar+Prism follow-up).

Match static Pygments colors to CM theme + remove em dashes from prose

Color parity fix (webr.css): chain `.CodeMirror` selector on cm-* rules so
our dark-theme colors outrank CodeMirror's bundled cm-s-default sheet
(previously loaded later, winning on equal specificity). Static Pygments
and post-click CodeMirror now render comments, strings, keywords, numbers,
operators, and function calls in identical colors.

Em dash sanitizer (_build/sanitize_dashes.py, new): one-time pass across
_posts/*.html and posts/*.md replaced 17,810 em dashes with `, ` in prose.
Preserves code blocks (<pre>/<code>/```), script/style tags, non-prose
attrs (href/src/class/id/...). Sanitizes prose attrs (title, alt, content,
aria-label) so SEO/a11y text is cleaned too. Integrated into md2html.py so
every new fragment is sanitized at write time.

Also cleaned em dashes from legacy root pages (font-comparison,
Top50-..., ggplot2-Tutorial-With-R, index) and dev comments in
_build/template.html. Updated write-post-interactive-v3 skill to instruct
future posts to avoid em dashes.

Final audit: 0 visible em dashes in any built page.