* change namespaces for agents and extension methods of the Microsoft.Agents.AI.OpenAI package
* remove unnecessary namespace
* remove unused namespaces
* fix compilation issues and rrolled back removed run methods
* sort usings
* add extension methods for AIAgent to work with OpenAI Responses primitives
* Move OpenAIChatClientAgent and OpenAIResponseClientAgent to samples
* sort usings
* sort usings
* Re-enable ImplicitUsings in samples and clean up NoWarns
* Fix dotnet format
* More dotnet format
* More dotnet format
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Co-authored-by: Chris <66376200+crickman@users.noreply.github.com>