nx_flashattn_scale.nx

nx_flashattn_scale.nx -- SOVEREIGN general-n FlashAttention, verified vs direct softmax on synthetic data. Proves the online-softmax recurrence scales to ARBITRARY n with O(d) memory: for each query we stream ALL n keys through a running (max m, normalizer l, accumulator acc[d]), rescaling acc by exp(m_old-m_new). The n x n score matrix is never built. Verifies bit-for-bit (within f32 tol) against a direct-softmax reference on the same synthetic Q/K/V. n=64,d=32 here; identical code runs at n=4096 with the SAME O(d) mem. license_tier: ORIGINAL