NVFP4 attention cache on W4A4 Qwen3-8B: static key smoothing is near-lossless, key rotations hurt
Short exploration note on the attention cache under the NVFP4 W4A4 baseline recipe (Qwen3-8B, RTN weights, SmoothQuant 0.5, 4/6 rule). This is simulated fake-quant on post-RoPE cached keys/values, NVFP4 16-blocks along head_dim, one calibration draw. Dev windows only: WT-val 32 windows and C4 calibr