Resolve a same-document OpenAPI reference "#/components//" BY NAME (C019 §A.1, C009).
Each pointer token is a map KEY (O(1) by-name); MUST throw if a key is absent; NEVER falls back to
positional/order lookup. Returns the referenced target. (Cross-document imports — C013 #72 — are not
yet implemented; a bare "#/..." is always same-document.)
Resolve a same-document OpenAPI reference "#/components//" BY NAME (C019 §A.1, C009).
Each pointer token is a map KEY (O(1) by-name); MUST throw if a key is absent; NEVER falls back to
positional/order lookup. Returns the referenced target. (Cross-document imports — C013 #72 — are not
yet implemented; a bare "#/..." is always same-document.)