feat: add PowerShell script to validate copyright headers

[littleKitchen]

Summary

Fixes #306

Adds Test-CopyrightHeaders.ps1 script that validates the presence of copyright and SPDX license headers in source files.

Changes

New Files

• scripts/linting/Test-CopyrightHeaders.ps1 - Main validation script
• scripts/tests/linting/Test-CopyrightHeaders.Tests.ps1 - Pester tests

Modified Files

• package.json - Added validate:copyright npm script

Features

• Scans .ps1, .psm1, .psd1, .sh files by default
• Checks for # Copyright (c) Microsoft Corporation. line
• Checks for # SPDX-License-Identifier: MIT line
• Handles shebang and #Requires statement positioning (checks first 15 lines)
• Outputs JSON results matching existing format
• Supports -FailOnMissing flag for CI integration
• Includes compliance percentage calculation

Testing

Pester tests cover:

• Files with valid headers
• Files missing copyright line
• Files missing SPDX line
• Files missing both headers
• Files with #Requires statements
• Parameter validation
• Output format validation

[katriendg]

Thanks - this looks good and covers the issue.

[codecov-commenter]

Codecov Report

❌ Patch coverage is 90.80460% with 8 lines in your changes missing coverage. Please review.
✅ Project coverage is 53.45%. Comparing base (4bb857d) to head (08070d1).

Files with missing lines	Patch %	Lines
scripts/linting/Test-CopyrightHeaders.ps1	90.80%	8 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #370      +/-   ##
==========================================
+ Coverage   52.44%   53.45%   +1.01%     
==========================================
  Files          17       18       +1     
  Lines        3110     3197      +87     
==========================================
+ Hits         1631     1709      +78     
- Misses       1479     1488       +9     

Flag	Coverage Δ
pester	53.45% <90.80%> (+1.01%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
scripts/linting/Test-CopyrightHeaders.ps1	90.80% <90.80%> (ø)

... and 1 file with indirect coverage changes

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

[katriendg]

Can you please review if you can improve code coverage? Thanks

[katriendg]

@littleKitchen please see the PowerShell failed check and review your Tests.
Also there are some improvements your can make to the Tests to follow patterns like in Invoke-PSScriptAnalyzer.Tests.ps1 (create all fixtures once in the top-level BeforeAll, passing glob pattern to -FileExtensions, ...).
You can use the PR-Review agent in the repo and get it to help you address the optimizations.
Thanks.