schemars was passing along the newlines from the doc comments. This
should make these closer to the markdown file versions we had in the old
agent.
Release Notes:
- N/A
This pull request introduces title generation and history replaying. We
still need to wire up the rest of the history but this gets us very
close. I extracted a lot of this code from `agent2-history` because that
branch was starting to get long-lived and there were lots of changes
since we started.
Release Notes:
- N/A
