Add 3-stage CIF fallback: pymatgen → CifParser(occ_tol=2) → ASE

Robust Zeo++: try -nt2 then -vornet, copy CIF first

Drop -r from Zeo++ command (incompatible with -vornet)

Fix Zeo++ command (-vornet with explicit output path) + parser for both formats

Initial PoreGCN web tool deployment