Adds endpoints to debug what has been persisted

[skrawcz]

This I think will be useful for production debugging; what's in my state?

This assumes:

1. You have the right dependencies with the server to load the right persister.
2. Not all persisters load via the constructor, so you can use a classmethod to be called to instantiate it.
3. Haven't exposed writing to state, but it's something we could do.

We'd probably want to couple this with a UI view.

Changes

• server run.py with two endpoints
• adds pydantic models returned

How I tested this

• not extensively, but it seems to work.

Notes

Checklist

• PR has an informative and human-readable title (this will be pulled into the release notes)
• Changes are limited to a single goal (no scope creep)
• Code passed the pre-commit check & code is left cleaner/nicer than when first encountered.
• Any change in functionality is tested
• New functions are documented (with a description, list of inputs, and expected output)
• Placeholder code is flagged / future TODOs are captured in comments
• Project documentation has been updated if adding/changing functionality.