[BUG] Conversation history is cleared unexpectedly

From my coworker Dan Cohn:

> instead of just resetting everything when the context window is exceeded, it would be really nice if you left space for a brief summary to be emittted. 'I understand that the conversation history has been cleared. I'm here to help you with any questions you might have about AWS services, coding, or other technical topics.' is pretty jarring, and is to be followed by me typing in a summary of the prior context so work can continue (or just giving up because thats a pain) in almost all cases.

This is unexpected behavior (clearing the conversation history) and we should address it.