Replace dynamic-range int8 with weight-only int8
Same change as efficientnet_b1 (merged earlier today), applied for consistency across the family: this repo's dynamic-range int8 is only mildly affected, but weight-only int8 is strictly closer to the float model at the same size reduction.
Measured against the torch float reference on real photos plus fixed random tensors at native resolution: dynamic min logit correlation 0.990 (top-1 6/6) vs weight-only 1.000 (top-1 6/6). The replacement file is quantized directly from this repository's published float32 file (litert quantize, recipe weight_only_wi8_afp32), so the weights are identical.
The model card is updated in the same commit: the metric entries for the removed dynamic file are dropped and a short quantized-variant note with the measured numbers is added.