intersect
Intersect L1 — path API (intersect, the package root).
Parses path-like glob strings into SegmentPatterns (via ./parse), adds
set-awareness (string | string[]), and exposes the registry. Pure — no
filesystem. Each primitive coerces Patterns to a set of SegmentPatterns,
then defers to the segment core (./segments). See
docs/planning/decisions/D-4FRD-intersect-api/layered-api.md.
No inference: a path-like string is the glob it literally is. A pattern with
NO wildcards is an exact-path match (src/siteA/components matches only that
path); a subtree is written explicitly (src/siteA/components/**).