fix: update version extraction to be more robust, ensure compatibility

[DevelopmentCats]

Description

Update version detection to always detect named module block, and extract version from same module block.
Ensure that script is completely compatible for all Unix environments.

Type of Change

• New module
• Bug fix
• Feature/enhancement
• Documentation
• Other

Testing & Validation

• Tests pass (bun test)
• Code formatted (bun run fmt)
• Changes tested locally

[Copilot]

Pull Request Overview

This PR fixes version extraction to be more robust by refactoring the version detection logic to ensure it extracts version information from the correct Terraform module block and improves Unix shell compatibility.

• Refactored version extraction to use a dedicated function that searches within specific module blocks
• Removed unused exit code constant and updated documentation
• Fixed shell compatibility issues with variable comparisons

---

_{Tip: Customize your code reviews with copilot-instructions.md. Create the file or learn how to get started.}