Multiturn conversation - Utilize the context ring buffer to allow context longer than maximum context window.

[psiddh]

On the Demo App, prompt

"How do you author a native Kernel Op on ExecuTorch" ?

Or keep chatting until Demo stalls or fails to give proper response

cc @larryliu0820 @mergennachin @cccclai @helunwencser @jackzhxng

[larryliu0820]

I can take a look. This is important to fix. thanks @kirklandsign for bringing to my attention.