Update project metadata, upgrade dependencies and add CI workflow

[sis0k0]

This PR upgrades the sample app to .NET 10 and updates the MongoDB C# driver to the latest available version. It also aligns the repo’s supporting docs and dev tooling so the project remains easy to run and review.

What changed

• Upgraded the project target framework to net10.0
• Updated mongodb.driver to 3.9.0
• Fixed launchSettings.json so dotnet run parses the profile correctly
• Updated README runtime/setup guidance to match .NET 10
• Aligned CI to 10.0.x
• Aligned the devcontainer app image to .NET 10
• Added a final devcontainer postStartCommand note for startup seeding

Validation

• dotnet build passes
• API starts successfully on http://localhost:5050
• GET /healthz returns Healthy
• GET /api/games returns 200 OK

Notes

• The app still seeds data on startup by default
• The root / route returns 404; Swagger is available at /swagger/index.html