Add validation scripts for all sample apps

[dluces]

Validation scripts for all sample apps to help ensure dependency auto-upgrades don't break them

[Copilot]

Pull request overview

This PR introduces a consistent, root-level PowerShell validation entrypoint (validate-sample.ps1) across sample apps, backed by shared tooling to perform local builds and lightweight runtime/browser smoke checks.

Changes:

• Added shared Playwright-based browser smoke tooling under Tools/sample-validation (Node + Playwright).
• Added shared PowerShell helper functions (Tools/powershell/SampleValidation.ps1) and per-sample validate-sample.ps1 scripts to standardize validation flows.
• Documented the new validation approach in README.md and ignored generated validation logs via .gitignore.

Reviewed changes

Copilot reviewed 12 out of 14 changed files in this pull request and generated 12 comments.

Show a summary per file

File	Description
Tools/sample-validation/package.json	Introduces Node tooling dependency for shared browser smoke checks.
Tools/sample-validation/package-lock.json	Locks Playwright dependency tree for the shared validation tooling.
Tools/sample-validation/browser-smoke.mjs	Implements the Playwright-driven browser smoke test runner.
Tools/powershell/SampleValidation.ps1	Adds shared PowerShell helpers for running commands, managing processes, and HTTP/browser smoke checks.
Custom Apps/webhook/validate-sample.ps1	Adds validation script for the webhook sample (runtime echo check).
Custom Apps/project-management/validate-sample.ps1	Adds validation script for the project-management sample (build + optional browser smoke).
Custom Apps/legal-docs/validate-sample.ps1	Adds validation script for the legal-docs sample (build + optional browser smoke).
Custom Apps/boilerplate-typescript-react/validate-sample.ps1	Adds validation script for the TypeScript React boilerplate (build + optional runtime + optional browser smoke).
Custom Apps/boilerplate-react-azurefunction/validate-sample.ps1	Adds validation script for the React + Azure Functions boilerplate (build + optional runtime + optional browser smoke).
Custom Apps/boilerplate-aspnet-webservice/validate-sample.ps1	Adds validation script for the ASP.NET web service sample (build + optional runtime smoke).
AI/ocr/validate-sample.ps1	Adds validation script for OCR sample (build/test + optional runtime + optional browser smoke).
AI/mcp-server/validate-sample.ps1	Adds validation script for MCP server sample (build + optional runtime health check).
README.md	Documents how to run sample validation scripts and their downgrade behavior.
.gitignore	Ignores generated local .validation log folders.

Files not reviewed (1)

• Tools/sample-validation/package-lock.json: Generated file

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.