Wiki Fold

Every claim has to trace back to a specific child entry, numeric facts get grep-verified, and the fold ID is derived from the input range so you get structural idempotency. Defaults to dry-run with stdout-only output because the repo's PostToolUse hook auto-commits on any Write, which means commit mode fires three separate commits for the fold page, index update, and log entry. Implements flat folds only, no hierarchical level stacking yet. The count-checking and extractive-only rules make it slower than a plain summarizer but you get audit trails and no hallucinated statistics.