Key difference from the reverted batched approach:
- Does NOT use torch::mm in a C++ loop (that was the reverted commit)
- Uses ixformer_torch_ext::ixformer_linear — the base image's optimized GEMM
- Same kernel the competitor (sub 168) uses via corex_moe.py
- Eliminates Python interpreter + dispatcher overhead per expert
- Links against _ixformer_torch.cpython-310.so (already in base image)
Decode: 1 Python call → 8 C++ ixformer_linear (vs 8 Python F.linear)
Prefill: 1 Python call → 64 C++ ixformer_linear (vs 64 Python F.linear)
