Qwen3.8 125B (6B active) Flash-Next

User reports Qwen3.8-Flash-Next at 31.05 t/s generation and 558.83 t/s prompt processing on an M3 Ultra 512GB. Setup is llama.cpp through llama-swap with the unsloth Q4_K_XL GGUF at 256,000 context, tested with llama-benchy. Prompt processing measured at pp1000 @ d1000 with 3312 ms time to first response; generation measured at tg500 @ d1000 with a peak of 31.67 t/s.