Tweaks-P1

[danielmacuare]

TLDR

Stabilises the CI pipeline by pinning tool versions, fixing a race condition in parallel Terraform validation via a provider cache warm-up step, updating all .terraform.lock.hcl files to include linux_amd64 hashes, and restructuring the docs tree.

Description

This branch bundles several reliability and housekeeping improvements made against the CI pipeline and project documentation. The core problem was non-deterministic failures in the terraform validate job: parallel terraform init processes were writing the same provider binaries to a shared cache directory simultaneously, causing a "text file busy" race condition. The fix is a sequential cache warm-up step that runs before the parallel validation fan-out. Version pins were also added for infracost, terraform-docs, and Terraform itself to prevent unexpected breakage from upstream releases. In parallel, the docs folder was reorganised into design/ and dev/ sub-trees, and a Python-based tf_validate.py script was introduced as a developer convenience wrapper.

Key Changes

• CI pipeline (.github/workflows/pipeline.yml): added a Cache Terraform providers step using actions/cache@v4, a sequential Pre-warm provider cache step that runs only on cache miss, and version pins for Infracost (v0.10.43), terraform-docs (v0.21.0), and Terraform (1.14.4).
• Lock files: regenerated all .terraform.lock.hcl files to include linux_amd64 provider hashes, ensuring terraform init succeeds on the GitHub Actions runner without downloading providers from scratch.
• Scripts: added scripts/tf_validate.py — a Python 3.11+ CLI (using typer + rich) that replicates the CI validation logic locally with a progress bar and summary table.
• Docs restructure: moved existing docs under docs/design/ and docs/dev/, added new pages for the CI pipeline, Terraform standards, TF validate tooling, and connectivity test results.
• Terraform version: bumped vars/terraform.tf and .terraform-version to 1.14.4.

[github-actions]

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