feat(testing): poc, use bats

[westonplatter]

Pre-Mege Todos

• This PR contains the terraform -> tf [Terraform, OpenTofu] logic in feat(tf): default to tofu and allow switching back to terraform #38. We'll need to merge that first and update this branch.

Changes

Adds BATS test infrastructure to Taskit and renames the terraform library to tf with support for switching between OpenTofu and Terraform.

Test Infrastructure

• GitHub Actions Workflow: Automated testing on PRs and main branch pushes (.github/workflows/test.yaml)
• BATS Test Suite: Comprehensive tests for terraform:plan task (tests/terraform_plan.bats)
• Documentation: Concise testing guide matching main README tone (tests/README.md)

[Gowiem]

@westonplatter I hate and love it at the same time. Let's 😎

[westonplatter]

@westonplatter I hate and love it at the same time. Let's 😎

I feel about the same. Asking a couple of hard core linux friends if there's a better way to get to the same end goal.

[westonplatter]

Thanks for the reviews @Gowiem and @gberenice.

While bats gives a higher degree of confidence, we heard from others that it was hard to scale it and other shell testing to handle medium to high complexity. Closing this while take their advice and look further into ways to test taskfiles.