Incremental rebuilds silently use STALE CUTLASS fused-MHA kernels

The general false-green principles (stale binary, wrong-artifact mtime) are summarised in the ort-test skill's "False-green taxonomy". This skill is the CUDA/CUTLASS-specific detail.

The gotcha (verification-integrity bug)

nvcc-generated depfiles do not track the CUTLASS fused-MHA headers under onnxruntime/contrib_ops/cuda/bert/cutlass_fmha/ (e.g. kernel_forward.h, fmha_launch_template.h). These headers are #included by the fmha_sm*.cu translation units, but the build system does not record that dependency.

Consequence: after you edit one of those headers, an incremental build.sh: