✨ Aspire 13.1.0 / MTP 2.0

[ricksu978]

1. What triggered this change? (PBI link, Email Subject, conversation + reason, etc)

Upgrade tooling + modernize test runner (Aspire 13.1.0 + Microsoft Testing Platform 2.0).

2. What was changed?

• Upgraded .NET Aspire packages to 13.1.0 and updated related project references
• Switched test runner to Microsoft Testing Platform via global.json and updated test projects accordingly
• Updated CI workflow to run tests with coverage and publish a coverage summary to the GitHub job summary
• Removed unused/outdated NuGet packages and aligned central package versions
• Health checks updated to
  • use the Aspire-named connection string
  • validate EF Core state by checking pending migrations

3. Did you do pair or mob programming?

No