Reduce mean cyclomatic complexity in action_setup.py

[coderabbitai]

Problem

The module .github/actions/rust-build-release/src/action_setup.py has a mean cyclomatic complexity of 5.57 across 7 functions, exceeding the threshold of 4.

This was identified during review of PR #166: #166

Context

The primary contributor to the elevated mean complexity is the bootstrap_environment() function, which has a cyclomatic complexity of approximately 12. Refactoring suggestions have been provided in the PR review comments to extract helper functions and reduce complexity.

Recommendation

Refactor the module to reduce the mean cyclomatic complexity below the threshold of 4 by:

• Extracting helper functions from bootstrap_environment() as suggested in PR comments
• Simplifying conditional logic where possible
• Applying the principle of single responsibility to complex functions

References

• Pull request: Ensure action_setup can import cmd_utils when run directly #166
• CodeScene analysis indicating mean complexity of 5.57
• Requested by: @leynos