* add deep-research sample * update sample description * update readme * remove duplicating section * Update dotnet/samples/GettingStarted/Agents/README.md Co-authored-by: westey <164392973+westey-m@users.noreply.github.com> * Update dotnet/samples/GettingStarted/Agents/Agent_Step18_DeepResearch/Program.cs Co-authored-by: westey <164392973+westey-m@users.noreply.github.com> * Update dotnet/samples/GettingStarted/Agents/Agent_Step18_DeepResearch/Program.cs Co-authored-by: westey <164392973+westey-m@users.noreply.github.com> * Use CreateAIAgentAsync extension method to create agent * move deep research agent sample to the catalog folder --------- Co-authored-by: westey <164392973+westey-m@users.noreply.github.com>