[INSTALL-5] nvidia-resiliency-ext build fails when CUDA_HOME and CPATH are not set

## Problem

When running the `uv` install command for Transformer Engine, the build of `nvidia-resiliency-ext` fails with an error stating `cuda.h` could not be found. The fix requires manually setting `CUDA_HOME` and `CPATH`, which is not documented.

## Steps to reproduce

Run the `uv` install command from the bare-metal installation guide on a system where `CUDA_HOME` is not set. The build fails with a missing `cuda.h` error.

## Suggested fix

Document that `CUDA_HOME` and `CPATH` must be set before running the install command. Alternatively, detect and set these variables automatically in the install flow.