Move source and test files from the standalone Hosting.AzureAIResponses project
into the Foundry package under a Hosting/ subfolder. This consolidates the
Foundry-specific hosting adapter into the main Foundry package.
- Source: Microsoft.Agents.AI.Foundry.Hosting namespace
- Tests: merged into Foundry.UnitTests/Hosting/
- Conditionally compiled for .NETCoreApp TFMs only (net8.0+)
- Deleted standalone Hosting.AzureAIResponses project and test project
- Updated sample and solution references
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>