- Add plan_to_sexp() to convert plan to S-expression format - Syntax highlighting for S-expressions: - Pink: special forms (plan, recipe, def, ->) - Blue: primitives (source, effect, sequence, etc.) - Purple: keywords (:input, :name, etc.) - Green: strings - Yellow: parentheses - Gray: comments Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>