* Intro group chat and refactor magentic. Fix as_agent()
* Cleanup and improvements
* Add as_agent docstring clarification
* Standardize orchestration messages to use agent-style inputs.
* Simplify group chat constructs
* Further cleanup
* Add sk to af group chat migration sample. Update README.
* Improvements and simplifications
* consolidating shared orchestration logic
* Further clean up
* Add group chat sample
* Improve typing
* Fix test imports
* Fix readme links
* Cleanup per PR Feedback
Evan Mattson