Fixes the seven defective v1 configs (psl2_4, psl2_8, psl2_9, psl3_4 held proper subgroups; q8, q16, q32 held dihedral groups). The other 87 configs keep their v1 element indexing exactly. Adds complexity_class, solvable, composition, seed and gdg_version to every metadata.json (compact separators). Rows drawn uniformly on lengths [3,1024], 100000 train / 20000 test per group, master seed 0, gdg 0.2.0.
