- ix_bridge.py: auto-discover ixformer .so files, pass as extra_ldflags
- ix_moe_bridge.cpp: fix mangled header from bad sed, add #include <optional>
- verify_single_gpu.py: also pass extra_ldflags during JIT compile
The undefined symbol _ZN8ixformer5infer12silu_and_mulERN2at6TensorES3_
lives in libixformer.so — need to explicitly link it.