Fork lineage tree for a public registry skill
Returns the fork tree rooted at this public registry skill.
Walks forked_from_skill_id reverse-recursively up to max_depth
levels. Each node carries the fork’s install_count, so the caller
can identify “popular forks” — community-iterated variants the
original author didn’t write but consumers gravitate to.
Only public (visibility='public') descendants are returned;
private forks living in consumer orgs are excluded (privacy).
Why this exists: install_count is a scalar on the root; without
a lineage view, the long tail of community-iterated forks is
invisible. Once a popular fork (install_count ≥ N) exists, surfacing
it gives consumers an alternative that’s been validated.