Deterministic, order-independent id derivation: the same (scope, originalId) pair
yields the same id on every client and every load. Used by the project-document
evaluator to give each placed reference's clones STABLE guids — scope is the
reference id carried in the document (plans/project-format-v0.md, must-fix #1).
Deterministic, order-independent id derivation: the same (scope, originalId) pair yields the same id on every client and every load. Used by the project-document evaluator to give each placed reference's clones STABLE guids — scope is the reference id carried in the document (plans/project-format-v0.md, must-fix #1).