docs(infrastructure): add terraform-docs tooling and improve developer experience

[WilliamBerryiii]

Description

This PR introduced terraform-docs as a first-class tool in the developer workflow with automated installation, contributing documentation, and linter exclusions for generated output. It also corrected Terraform variable placement in the automation and vpn modules to align with repository conventions, and normalized markdown table formatting across documentation files.

Terraform-docs Tooling and Developer Setup

Added terraform-docs integration with both developer setup scripts and contributing documentation to standardize how Terraform module documentation is generated and maintained.

• Added a Documentation Generation section to docs/contributing/infrastructure-style.md covering .terraform-docs.yml configuration, a table of generated TERRAFORM.md file locations across all five modules, regeneration commands, and quality standards for generated output.
• Added terraform-docs 0.21.0 to the prerequisite tools table in docs/contributing/prerequisites.md with a verification command.
• Added terraform-docs installation logic to setup-dev.sh with architecture detection (uname -m mapping for x86_64 → amd64, aarch64/arm64 → arm64) and OS detection via uname -s.
• Added terraform-docs installation logic to setup-dev.ps1 with cross-platform architecture and OS detection for PowerShell environments.
• Excluded **/TERRAFORM.md from spell checking in .cspell.json and from markdown linting in .markdownlint-cli2.jsonc since these files are generated output.
• Added lastexitcode to .cspell/general-technical.txt to support PowerShell $LASTEXITCODE references in the setup script.

Terraform Variable Consistency

Moved the tags variable from variables.core.tf to variables.tf in two modules to follow the repository convention that core variable files contain only the five standard variables (environment, resource_prefix, instance, resource_group, and optionally location).

• Relocated tags from infrastructure/terraform/modules/automation/variables.core.tf to variables.tf with an improved description under a // === Tags === section separator.
• Relocated tags from infrastructure/terraform/modules/vpn/variables.core.tf to variables.tf with an improved description under a // === Tags === section separator.
• Removed default = "dev" from environment and default = null from location in the automation module's core variables, making them required at the caller level consistent with other modules.

Markdown Table Formatting

Normalized table pipe alignment across 17 documentation files. These are whitespace-only changes that do not alter rendered content.

Related to #328

Type of Change

• 🐛 Bug fix (non-breaking change fixing an issue)
• ✨ New feature (non-breaking change adding functionality)
• 💥 Breaking change (fix or feature causing existing functionality to change)
• 📚 Documentation update
• 🏗️ Infrastructure change (Terraform/IaC)
• ♻️ Refactoring (no functional changes)

Component(s) Affected

• infrastructure/terraform/prerequisites/ - Azure subscription setup
• infrastructure/terraform/ - Terraform infrastructure
• infrastructure/setup/ - OSMO control plane / Helm
• workflows/ - Training and evaluation workflows
• training/ - Training pipelines and scripts
• docs/ - Documentation

Testing Performed

• Terraform plan reviewed (no unexpected changes)
• Terraform apply tested in dev environment
• Training scripts tested locally with Isaac Sim
• OSMO workflow submitted successfully
• Smoke tests passed (smoke_test_azure.py)

Documentation Impact

• No documentation changes needed
• Documentation updated in this PR
• Documentation issue filed

Bug Fix Checklist

Complete this section for bug fix PRs. Skip for other contribution types.

• Linked to issue being fixed
• Regression test included, OR
• Justification for no regression test:

Checklist

• My code follows the project conventions
• Commit messages follow conventional commit format
• I have performed a self-review
• Documentation impact assessed above
• No new linting warnings introduced

[github-actions]

Dependency Review

✅ No vulnerabilities or license issues or OpenSSF Scorecard issues found.

Snapshot Warnings

⚠️: No snapshots were found for the head SHA 8834ebb.

Ensure that dependencies are being submitted on PR branches and consider enabling retry-on-snapshot-warnings. See the documentation for more information and troubleshooting advice.

Scanned Files

None

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 43.58%. Comparing base (a82dd68) to head (8834ebb).
✅ All tests successful. No failed tests found.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #365   +/-   ##
=======================================
  Coverage   43.58%   43.58%           
=======================================
  Files         242      242           
  Lines       14840    14840           
  Branches     1903     1855   -48     
=======================================
  Hits         6468     6468           
  Misses       8082     8082           
  Partials      290      290           

Flag	Coverage Δ		*Carryforward flag
pester	79.87% <ø> (ø)
pytest	6.89% <ø> (ø)		Carriedforward from 329de7b
pytest-dataviewer	61.98% <ø> (ø)
vitest	50.72% <ø> (ø)

*This pull request uses carry forward flags. Click here to find out more.

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