Implements four new mdcms fenced-block types:
tab-underline / tab, tab-filled,
accordion-underline / accordion, accordion-filled
Each block reads items: from a YAML body. Tab state and accordion
open/close are managed with aria-selected / aria-expanded and
data-open attributes. Markdown content inside each item is rendered
with the same pipeline as the surrounding page.
Adds computeDerivedTokens() — called on every applyTheme() — which
computes --mdcms-bar, --mdcms-filled-bg/border/fg, --mdcms-strip-border
from the active palette. Uses HSL chroma (S × (1-|2L-1|)) instead of raw
HSL S for the bold-nav heuristic, avoiding a false-positive on near-white
nav colours like the default #F8FAFC.
Adds app/pages/tabs-accordions.md as a visual test page and
docs/unreleased.md to track this change ahead of the next release.
https://claude.ai/code/session_01SFMh7PDxJjvvo5dYbCCFFs
