Align repository with TemplateDotNetLibrary template patterns

[Copilot]

Pull Request

Description

Aligns this repository with the TemplateDotNetLibrary template using the repo-consistency agent, then runs remaining agents for incremental improvements.

Template Consistency

• Migrate .sln → .slnx
• Replace .markdownlint.json with .markdownlint-cli2.jsonc
• Simplify .editorconfig to match template (adds csharp_prefer_braces = true:warning, file-scoped namespace enforcement)
• Modernize build/lint scripts (build.sh, lint.sh, etc.)
• Replace manual SBOM tooling (sbom-tool, spdx-tool) with Microsoft.Sbom.Targets in csproj
• Update buildmark 0.2.0 → 0.3.0; reorder and clean .config/dotnet-tools.json
• Merge template dictionary additions into .cspell.json; add ignore patterns to .yamllint.yaml

CI/CD Workflows

• Reorganize build.yaml with section comments matching template structure
• Add title.txt to all pandoc definition.yaml input-files (was missing — would have broken PDF generation)
• Fix test-results download pattern to '*test-results*' matching template
• Simplify release.yaml; add --skip-duplicate to NuGet push
• Rename PDF outputs: drop DemaConsulting. prefix (e.g. "TestResults Build Notes.pdf")
• Rename artifact from documentation → documents

Code Improvements

• Add input validation (ArgumentNullException/ArgumentException) to all public Serialize/Deserialize methods, using ArgumentNullException.ThrowIfNull per CA1510
• Narrow catch in Serializer.Identify from catch-all to System.Xml.XmlException
• Fix braceless if statements in JUnitSerializer.cs and TestHelpers.cs

Requirements & Tests

• Restore net8.0@/net9.0@/net10.0@ framework-specific test prefixes (agent had incorrectly removed them, breaking evidence traceability)
• Add REQ-FUNC-012 through REQ-FUNC-021 covering additional test outcomes and features
• Add 12 new tests using Assert.ThrowsExactly<T>() for input validation (53 total, up from 41)

Potential Template Back-ports

• TestResults has a comprehensive ARCHITECTURE.md — template could benefit from a placeholder
• Original .editorconfig had more granular formatting rules (newlines, spaces, indentation) lost in simplification

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 unit 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 .

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

All 53 tests pass on net8.0, net9.0, and net10.0. CodeQL and code_review tools timed out during the PR workflow; no security-sensitive code paths were modified (changes are config alignment, input validation, and tests).

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[Malcolmnixon]

@copilot Please consider the following Sonar warnings:

src/DemaConsulting.TestResults/IO/JUnitSerializer.cs(61): INFO CODE_SMELL [external_roslyn:CA1510] Use 'ArgumentNullException.ThrowIfNull' instead of explicitly throwing a new exception instance  
src/DemaConsulting.TestResults/IO/TrxSerializer.cs(78): INFO CODE_SMELL [external_roslyn:CA1510] Use 'ArgumentNullException.ThrowIfNull' instead of explicitly throwing a new exception instance  

[Copilot]

@copilot Please consider the following Sonar warnings:

src/DemaConsulting.TestResults/IO/JUnitSerializer.cs(61): INFO CODE_SMELL [external_roslyn:CA1510] Use 'ArgumentNullExcep...

Fixed in 95ca4a9 — replaced the explicit new ArgumentNullException(nameof(results)) throws with ArgumentNullException.ThrowIfNull(results) in both JUnitSerializer.cs and TrxSerializer.cs.