Added unit test project, action and status badge to TechnitiumLibrary

[zbalkan]

No description provided.

[Copilot]

Pull request overview

This PR introduces a new MSTest-based unit test project, sets up a GitHub Actions workflow to build and run tests on Windows/MSBuild, and surfaces test status via a README badge.

Changes:

• Added TechnitiumLibrary.UnitTests MSTest project targeting .NET 9 and referencing the main library.
• Enabled MSTest parallelization at method level via MSTestSettings.cs.
• Added a Windows/MSBuild-based GitHub Actions workflow for restore/build/test and linked it with a status badge in the README.

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
TechnitiumLibrary.sln	Registers the new TechnitiumLibrary.UnitTests project and includes it in Debug/Release build configurations.
TechnitiumLibrary.UnitTests/TechnitiumLibrary.UnitTests.csproj	Defines the MSTest-based unit test project targeting net9.0 and referencing the main library project.
TechnitiumLibrary.UnitTests/MSTestSettings.cs	Configures MSTest to run tests in parallel at the method level via an assembly-level attribute.
README.md	Adds a “Quality Assurance” section with a GitHub Actions status badge for the new unit-testing workflow.
.github/workflows/unit-testing.yml	Sets up a Windows/MSBuild GitHub Actions workflow to restore, build, and run tests for the solution (currently with a broken path for the test project).

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