Add CI workflows for docs, Terraform, and PowerShell checks

[doherty100]

Purpose

Adds automated CI checks that run on every pull request targeting vnext (and on pushes to vnext). The checks are static-analysis only — no Azure deployment and no credentials required.

Workflows (.github/workflows/)

Workflow	Checks
ci-docs	markdownlint-cli2 (pinned 0.22.1) + lychee offline/internal link check
ci-terraform	terraform fmt -check -recursive (Terraform 1.15.6) + tflint --recursive (v0.61.0, existing .tflint.hcl)
ci-powershell	PSScriptAnalyzer 1.24.0, fails on Error/Warning

All run with contents: read only and concurrency-cancel.

New configuration

• .markdownlint.jsonc (rules) + .markdownlint-cli2.jsonc (globs/ignores — excludes node_modules, the frozen retired module, and the agent copilot-instructions.md)
• PSScriptAnalyzerSettings.psd1 — default rules minus documented exclusions for intentional patterns / false positives in this automation codebase (Write-Host, the project's own Write-Log helper, required plaintext→SecureString, uniform run-command parameter contracts, BOM on cross-platform pwsh 7, singular-noun / ShouldProcess style)

Baseline fixes (so the checks pass on the current tree)

• Terraform: fmt normalization across 5 files; scoped # tflint-ignore comments on two intentional unused-variable declarations
• Markdown: PR/issue templates, NVMe README (code-fence languages, blank lines, escaped table pipes), LICENSE trailing newline
• PowerShell: 11 real findings fixed (unused vars → $null =, empty catch {} → Write-Verbose, hardcoded host → variable); all scripts re-parsed clean

Documented in CONTRIBUTING.md with local reproduction commands.

Does this introduce a breaking change?

[ ] Yes
[x] No

Pull Request Type

[ ] Bugfix
[x] Feature
[ ] Code style update (formatting, local variables)
[ ] Refactoring (no functional changes, no api changes)
[ ] Documentation content changes
[ ] Other... Please describe:

How to Test

• Open this PR and confirm the ci-docs, ci-terraform, and ci-powershell checks run and pass.
• Locally: see the Continuous Integration section in CONTRIBUTING.md.

What to Check

• All three CI workflows pass on the current baseline.