Function native_q2_mmq_enabled 

pub fn native_q2_mmq_enabled() -> bool

Sub-flag gating the native Q2_0 MMQ prefill path (ATLAS_GGUF_NATIVE_Q2_MMQ=1). Default off: keep the transient-dequant stopgap so the two can be A/B’d on GPU. (ATLAS_GGUF_NATIVE_Q2 still gates keep-packing overall — this only chooses how the kept-packed weight is consumed in PREFILL.)