Agent lacks awareness of org-specific internal package versions

### Description

Direct customer feedback:

> When upgrading a .NET 8 application to .NET 10, the agent didn't know which version of the customer's internal NuGet package to target. The developer had to manually specify the version because the agent wouldn't know the correct org-specific version on its own.

Expected Behavior:

The agent should support org-level configuration for internal package version targets or prompt the user when encountering internal/private NuGet packages with uncertain version targets.