docs(tests): npm/PowerShell wrappers, remove legacy shells (#562 4/4)

[WilliamBerryiii]

Part 4 of 4 splitting #562 into reviewable PRs.

Parent: #562
Depends on: #569

Scope

Update docs and existing blueprint tests to point at the npm/PowerShell wrappers, then delete the legacy shell scripts. Deletions are safe only after PRs 1–3 are live.

Files

• blueprints/full-single-node-cluster/README.md
• blueprints/full-single-node-cluster/terraform/README.md
• blueprints/full-single-node-cluster/tests/README.md
• blueprints/full-single-node-cluster/tests/deploy_bicep_test.go
• blueprints/full-single-node-cluster/tests/deploy_terraform_test.go
• docs/contributing/testing-validation.md
• docs/getting-started/blueprint-developer.md
• Delete blueprints/full-single-node-cluster/tests/run-contract-tests.sh
• Delete blueprints/full-single-node-cluster/tests/run-deployment-tests.sh

Acceptance criteria

• npm run mdlint-fix clean.
• grep -rn "run-contract-tests.sh\|run-deployment-tests.sh" . returns no live references outside .copilot-tracking/.
• All npm run targets referenced in updated docs exist in package.json.