nx_symmetry_group.nx

nx_symmetry_group.nx -- multi-axis symmetry detector. Generalizes nx_compose_h_symmetry + nx_compose_v_symmetry from horizontal/vertical bilateral to: * diagonal mirror (axis x = y) * anti-diagonal mirror (axis x = -y) * 180-degree rotational * 90-degree rotational (square only) * translational periodic Returns per-axis Q10 scores + the sealed-enum kind of the dominant symmetry + a composite verdict. Multiple axes can fire concurrently (a square checkerboard has H + V + DIAG + 4_FOLD + TRANSLATIONAL all near max); the report carries them all so downstream tooling sees the full symmetry group, not just the maximum. Cross-modal kernel: the algorithms here operate on any indexed array. Today's signature takes *Image, but the substrate will later generalize to spectrograms, attention heatmaps, terrain arrays, palindrome detection over token streams, etc. Sealed-enum SymmetryKind (gap-2 mitigation via constants): NX_SYM_NONE 0 NX_SYM_H_BILATERAL 1 NX_SYM_V_BILATERAL 2 NX_SYM_DIAGONAL 3 NX_SYM_ANTIDIAGONAL 4 NX_SYM_2_FOLD_ROT 5 NX_SYM_4_FOLD_ROT 6 NX_SYM_TRANSLATIONAL 7 genealogy_id: weyl_1952_symmetry + tyler_1995_visual_symmetry + wagemans_1995_psychophysics_symmetry lineage_id: multi_axis_symmetry_group_q10