v1.3.0

Brings the /reference/ and /style/ pages and the CMS editor in line with musings, adapted to this site's own design — plus heading anchors, phrase-highlighted margin notes, a hand-drawn section break, drafts and slug overrides, and fixes so shortcodes work inside posts and the Atom feed renders correctly.

• feat: /reference/ is now musings' reference page content, adapted — reference.md replaced with musings' text; only sentences that described musings' own look (Docs chrome, grey desk, comment rail, browser link colour) or were wrong (-- is an en dash, not an em dash) were reworded. The fourth-level heading sample now uses #### (musings' source used ###). The intro line and the "not implemented" notes are gone; reference-page.njk no longer prints an intro
• feat: heading anchors — markdown-it-anchor gives every heading an id and links it to itself; { #id } still overrides
• feat: {% marginnote "phrase" %} — the phrase is highlighted in the paragraph after the note (src/js/margin-notes.js), hover/focus links the two
• feat: section break — --- / *** in markdown now draws one of the hand-drawn dividers used between posts in a list (md.renderer.rules.hr), instead of a plain 1px line. Musings' page break is not carried over: it only makes sense in a paginated-document look, so the reference page's "Page break" section became "Section break"
• fix: callout and marginnote shortcodes printed literally inside posts, because post bodies are rendered by markdownify without Nunjucks. markdownify now expands them
• fix: Atom feed showed literal HTML tags — feed.njk wrapped the post body in <![CDATA[…]]> but Nunjucks also HTML-escaped it. Body now goes in <content type="html"> as escaped text (the standard form). Never noticed because no posts existed
• fix: feed links — heading anchors and footnote links resolved to <site>/#id (the home page). New feedContent filter unwraps heading self-links, points footnote links at the post, and swaps the SVG section break for an <hr>
• feat: /style/ rebuilt in musings' structure and read from styles.css's :root block by src/_data/tokens.js — no more hardcoded hex/scale lists. Adds line heights, shape and layout, and the components section (badges, dividers and section break, margin note, callouts); removes the unused .styleguide-* CSS
• feat: CMS editor — draft toggle, optional slug override, field hints, label_singular, ASCII slugs
• feat: draft: true posts are hidden from the home list, category pages, feed and sitemap in a build (published filter); slug front matter overrides the filename in posts.js
• feat: admin page — Sveltia is no longer pinned to 0.211.2; it loads the latest from unpkg, as musings does. The admin is now named "OTB CMS" (login screen, tab title, application-name, apple-mobile-web-app-title); tab title pinned, noindex, nofollow, noarchive, noimageindex, theme colour and icon links
• fix: About page scrolled sideways on phones — the anatomy diagram is a fixed 520px <img> with no max-width; it now shrinks to fit
• infra: added markdown-it-anchor; src/js/ is passthrough-copied
• docs: corrected the image-generation notes in APP.md/CLAUDE.md (Playwright + ImageMagick, not resvg; the OG PNG is build output, not committed) and the URL env var (set in deploy.yml); README layout and file map updated; FUTURE.md no longer lists the removed newsletter form or calls Playwright unused, and now tracks the unused @resvg/resvg-js/opentype.js dependencies