docs(adr): scope the descriptor split reference
Merged
TH
7d ago+2+2+0123456789-1-1-0123456789
Summary
Narrow ADR 0028's reference to ADR 0027 to statement-neutral descriptor-root hub splits. Platform loading remains governed by ADR 0019 and its owning decisions. This corrects an overbroad reference without changing a loading rule.
One documentation file changed. Follow-up to merged #4078 and its review; part of #4045.
Validation
Head: 4c15c123e11724161be18a37b511391d70ebf59c.
Full-repository format passed. The exact-head affected invocation passed with zero selected checks; runtime tests do not apply to this reference correction. CI remains authoritative for its selected lanes.