Interface MutationEntityByIdIndex

Minimal entity-by-id index shape. Compatible with Map<number, EntityRef> and the parser's CompactEntityIndex. Only the read methods are required — the overlay never mutates the underlying index.

interface MutationEntityByIdIndex {
    size: number;
    get(expressId: number): MutationEntityRef | undefined;
    has(expressId: number): boolean;
    keys(): IterableIterator<number>;
}