Fix path traversal vulnerability and add build/lint convenience scripts

[Copilot]

Pull Request

Description

Systematic repository analysis revealed a critical path traversal vulnerability and missing convenience scripts for local development workflow.

Security Fix

PathHelpers.cs - Path traversal bypass in defense-in-depth validation:

// BEFORE: Vulnerable to similar directory names
if (!fullCombinedPath.StartsWith(fullBasePath, StringComparison.OrdinalIgnoreCase))

// Attack: basePath="/project" + relativePath="ion/evil" → "/projection/evil" ✓ passes

// AFTER: Robust validation
var relativeCheck = Path.GetRelativePath(fullBasePath, fullCombinedPath);
if (relativeCheck.StartsWith("..") || Path.IsPathRooted(relativeCheck))

Template Alignment

• Build/Lint Scripts: Added build.{sh,bat} and lint.{sh,bat} for local development workflow

Type of Change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation update
• Code quality improvement

Related Issues

Pre-Submission Checklist

Before submitting this pull request, ensure you have completed the following:

Build and Test

• Code builds successfully: dotnet build --configuration Release
• All tests pass: dotnet test --configuration Release
• Code produces zero warnings

Code Quality

• Code formatting is correct: dotnet format --verify-no-changes
• New code has appropriate XML documentation comments
• Static analyzer warnings have been addressed

Quality Checks

Please run the following checks before submitting:

• Spell checker passes: cspell "**/*.{md,cs}"
• Markdown linter passes: markdownlint "**/*.md"
• YAML linter passes: yamllint '**/*.{yml,yaml}' (requires yamllint installation)

Testing

• Added unit tests for new functionality
• Updated existing tests if behavior changed
• All tests follow the AAA (Arrange, Act, Assert) pattern
• Test coverage is maintained or improved

Documentation

• Updated README.md (if applicable)
• Updated ARCHITECTURE.md (if applicable)
• Added code examples for new features (if applicable)
• Updated requirements.yaml (if applicable)

Additional Notes

Changes identified via repo-consistency-agent and code-quality-agent. All 127 unit tests + 4 self-validation tests pass. Agent report files remain local only (excluded via .gitignore).

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[Malcolmnixon]

The README.md is getting too long and loaded with stuff not necessary for users. Please remove the following new sections:

• Building from Source
• Project Structure
• CI/CD Pipeline

These will be handled in separate documents.

[Copilot]

Removed the three sections (Building from Source, Project Structure, CI/CD Pipeline) from README.md in commit 434dbc7.