Code view: SSR now uses same highlighting logic as client update-code-highlight
(bg-amber-100 for current step, font-bold for active, opacity-40 for future).
steps-to-preview: pure function that replays step machine as SX expression
tree — intended for isomorphic preview rendering. Currently working for
simple cases but needs fix for partial step counts (close-loop issue).
Close steps now carry open-attrs/open-spreads for steps-to-preview.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>