nx_pattern_emit6_erfc.nx

nx_pattern_emit6_erfc.nx -- PATTERN EMITTER: MATH_KERNEL / ERFC_CF (DLMF ch7 rung 2, ME2-ERF-002). The Builder authors f64 erfc from the SOVEREIGN spec (nx_mathspec_erfc). The emitter contains STRUCTURE only -- the Laplace continued fraction (backward recurrence, a_k=k/2) -- and every NUMBER written into the kernel comes from the spec table c[] (c[0]=1/sqrt(pi) FIRST so the tamper's litskip=0 targets the load-bearing scale). Domain 1.75..6; the f64 ULP bar vs the sovereign oracle is the Engineer's separate gate (_f64_erfc_gate); the emitted test checks ALGORITHM INVARIANTS only. license_tier: ORIGINAL