merge: lane/gemma-oracle-20260819 @ 78353d5e24 — MEMRA_FAST=0 illegal-address fix: matmul_pre guarded six raw-f32 arms and missed the seventh (!uses_q8_1_fast -> self.matmul), the only arm MEMRA_FAST=0 opens; now refuses loudly, and the batched gemma-4 arm materializes the f32 only under MEMRA_FAST=0 via rms_norm_decode (bit-identical to rms_norm_q8_1's reduction). Daily path bit-unchanged 3/3. SCOPE: verified on gemma-4-12B Q4_0, NOT the served 31B Q6_K.