tree.sx, reuses ureach-bfs. 158/158 across 9 suites. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
lib/relations/tree.sx over reach/ancestors/rnode — no new Datalog closures. 126/126. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>