nx_npy_gate.nx

nx_npy_gate.nx -- proves the .npy parser reads what is there and REFUSES the three things that corrupt silently. procgen PG38's opening move, gateable on its own before any model byte is fetched. WHY THE NEG-CONTROLS ARE THE POINT. A forward-only suite here would pass for a parser that ignores fortran_order, guesses an itemsize and trusts the declared shape -- and every one of those returns PLAUSIBLE NUMBERS rather than an error. A transposed basis, a factor-of-two offset walk, or a read past the end of a member all look like data. So T7-T10 are the load-bearing teeth. THE FIXTURE IS ASSEMBLED AT RUNTIME, never read from disk: the parser's own subject is a byte layout, so a byte layout built in memory is the honest fixture and there is no file to go stale. The teeth are ARITHMETIC over that layout (count = product of dims; data_off + count*itemsize = total), which makes them their own oracle in the mathcore sense -- no second implementation to disagree with. license_tier: ORIGINAL expect_exit: 0