docs: article contract gains embeds — build-time code from git.nech.pl/github/raw, directive islands

/admin serves Sveltia CMS from a pinned jsdelivr bundle (0.229.0) with a
cms-config-url link to ./config.yml; HTML comment documents the Decap
fallback (same config, swap the script). Backend points at git.nech.pl
with base_url + api_root for the self-hosted instance, PKCE app_id
filled in, implicit grant noted as fallback. Blog collection fields
match the existing frontmatter; media folder public/images/blog with
public_path /images/blog. scripts/new-share-token.mjs prints a random
6-char token for the unlisted draft links.

Drafts with a well-formed `share` token in frontmatter ship to prod at
/blog/d/<slug>-<token>: robots noindex/nofollow, no OpenGraph, token
re-checked at render so a guessed slug renders nothing, tokenless drafts
get no unlisted path. Article markup factored into a shared PostArticle;
the public listing and /blog/[slug] keep filtering drafts out.

Also: static export requires at least one prerendered variant per dynamic
route, and prod currently has zero published posts — emit a 404 sentinel
param so the export still ships (build broke at HEAD for this reason).

Same grammar as Clarté TDAH (clarte kit: ProgressHeader, QuestionCard,
OptionPills, useDigitKeys), linear 25-item flow: consent-gated home with
optional gender, intro, auto-advancing questions, recap with jump,
results with total band + percentiles vs autistic and non-autistic
norms, five interpretation caveats, copyable consult sentence, jspdf
report. FR at /tsa, EN at /asd, mirroring /tdah + /adhd.

25 items Likert 1-7 (verbatim Hull 2019 in EN, our translation in FR,
flagged non-validated), items 3/12/19/22/24 reversed, subscales
compensation/masking/assimilation. Percentiles via normal CDF on the
Hull 2020 gender-matched norms; Baker 2024 descriptor bands on the
total score. Storage contract catq:v1, same discipline as clarte:v1.

Adds remark-gfm/directive/parse/rehype, rehype-pretty-code, shiki,
unified, unist-util-visit; retires remark/remark-html. Under PnP there
are no real node_modules dirs — cache zips live under paths *containing*
/node_modules/, so jest's transformIgnorePatterns now only excludes the
css module mocks, keeping the ESM-only unified chain transformable.

The site ships as flat files (out/) served by self-hosted nginx; every
route prerenders at build. next/image ships originals (unoptimized) —
optimization needs a server. The two parvagues revalidate = 60 exports
go with ISR; rebuild-on-push replaces it.

The one render chain: remark-gfm, remark-directive (mapped-tag escape
hatch for future embed islands), rehype-figure, rehype-pretty-code with
vesper highlighting at build time. Shipped pages are flat HTML with
inline token colors and zero client JS.

- lib/markdown.ts mints all /blog HTML; lib/blog.js binds the section
- app/blog + app/blog/[slug] on the App Router (SSG, generateMetadata);
  app/post/[id] and lib/posts.js removed with the route
- content/posts moved to content/blog; the 2021 entries are draft:true,
  hello-world-again is the one published post (engine fixture: figure
  captioning, shiki, GFM table) with its edge.png image
- yarn post / yarn post:image scaffold posts and stage images
- e2e smoke routes follow the rename