feat: add event logging api and more tracing

[lalo]

PR moved to: #2478

Related:
#2415

Why are these changes needed?

Related issue number

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[sonichi]

This partially addresses #2423. Let's add test coverage and fix the code format error.

[cheng-tan]

existing unit test is in test_logging.py, integration test in test_agent_logging.py. It would be nice to check the schema of the json_state instead of free format

[lalo]

I went for free format of json to simplify calling site of logging, as long as it can be serialized to json I'm fine with it. In an ideal world we would have full normalized columns in this sqlite, but don't want to deal with that complexity and also don't want to restrict what types of keys and values they can log. Also, this allows same API to be used in multiple places - which is helpful for this 'event' state scenario and less for more formalized concepts like a 'new agent instance'.

[ekzhu]

We can log more events in the future PRs.

[ekzhu]

@henry-zhang-bohan This PR partially address your issue regarding observability #2423 . There are separate PRs like #2329 to use different logging destination.

[sonichi]

Thanks. There is a test requiring openai CI. Could you remake a PR from the upstream repo to run that CI please? Thank you.

[lalo]

moved to #2478