* .NET: Refactor A2A hosting registration into A2AServerServiceCollectionExtensions
- Rename A2AHostingOptions to A2AServerRegistrationOptions
- Move server registration logic from A2AEndpointRouteBuilderExtensions
and AIAgentExtensions into new A2AServerServiceCollectionExtensions
- Remove A2AProtocolBinding and AIAgentExtensions (consolidated)
- Update samples and tests to use the new registration API
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
* address copilot comments
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Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>