The pinned b9360 cuda-13.1 Windows fallback for Blackwell (sm_120) only fired
when the driver advertised CUDA >= 13.1. The mainstream Blackwell branch ships
the r580 driver that reports CUDA 13.0, so those hosts missed the pin, were
gated off the in-release 13.3 build, and dropped to the CPU-only cuda-12.4
build.
b9360's binary is native sm_120a SASS (no PTX, so no JIT) and its bundled
runtime is cuda-13.1 cudart; both run on a 13.0 r580+ driver under CUDA
minor-version compatibility. Lower _PINNED_BLACKWELL_DRIVER_FLOOR to (13, 0) so
the pin covers the 13.0 branch too. The generic published-runtime gate stays
conservative (an unverified in-release 13.1 build is still gated off 13.0); only
the specific, hash-pinned, SASS-verified b9360 build is extended.
Refs #5887.