pub fn build_walkthrough_markdown(
guide: &StandardWalkthroughGuide,
root: &Path,
viewed: &[String],
) -> StringExpand description
Build a paste-into-PR markdown rendering of the existing walkthrough guide.
Mirrors the human terminal tour: a Focus line, Stage 1 (affects code outside the
PR) and Stage 2 (self-contained) sections partitioned by concern_lens, with synthesized
badges as inline code spans, then a collapsible Cleared panel. The JSON guide
path is untouched; this is the only NEW walkthrough markdown surface. No ANSI.
viewed is the root-relative file list the local ledger marked viewed (the
--mark-viewed state). Viewed files collapse out of their stage and into the
Cleared panel, and the Cleared summary reports the viewed count, so the
markdown surface honors --mark-viewed the same way the human surface does
instead of silently ignoring it.