Use the same nightly toolchain in the CLI

[ia0]

No description provided.

[gemini-code-assist]

Code Review

This pull request updates the CLI to use the same nightly toolchain as defined in the repository's rust-toolchain.toml. It introduces a helper function to check for command existence and a script to synchronize the toolchain version. My review focuses on the robustness of the new script and the public helper function. I've identified a potential bug in the shell script that could cause it to fail with certain toolchain names, and a correctness issue in the new exists function that should be addressed by documenting its limitations.

[ia0]

/gemini review

[gemini-code-assist]

Code Review

This pull request aims to standardize the Rust nightly toolchain used by the CLI, aligning it with the version specified in rust-toolchain.toml. This is achieved by introducing a nightly_toolchain helper that modifies cargo commands when rustup is available. A new sync.sh script is added to keep the toolchain version in the source code synchronized with rust-toolchain.toml. While the overall approach is sound, the sync.sh script contains bugs that prevent it from working correctly. My review provides a critical fix to make the script robust and functional.