Snow: align schema space with the deployed inference graphs (max 14,419 grouped columns, ACS_2); gold re-expressed in that space, n_schema_columns == len(schema), 0 unresolved / 0 empty

One consistent grouped-node space for Spider 2.0: schemas as flat node lists, n_schema_columns == len(schema), gold re-expressed in system space (31 snow CRYPTO remaps, lite family space + SQL-disambiguated shards); strict exact-membership checker

Add Spider/BIRD/Spider2.0-Snow(256) schema-linking eval sets + KaSLA case-by-case comparison