nx_zimage_flashattn_verify.nx

nx_zimage_flashattn_verify.nx -- SOVEREIGN FlashAttention (online-softmax) SDPA, verified EXACT vs oracle. The O(n)-memory attention: instead of building the n x n score matrix, softmaxing, then weighting V, we STREAM keys into a running accumulator, rescaling it by exp(m_old - m_new) as the running max grows. Peak memory is O(d) per query (the accumulator + 3 scalars m,l,a), NOT O(n) -- so it scales to any n without materializing scores. This organ proves the recurrence is NUMERICALLY IDENTICAL to standard softmax attention (verifies vs the same oracle ao_pre as the direct SDPA). Lossless, not an approximation. Uses a LOCAL accumulator (no mmap scratch in the loop) per the nx_cc codegen lesson. No 3rd party. license_tier: ORIGINAL