GA "Data Storage" check implementation and documentation

[BigLep]

Done Criteria

1. There is public documentation for what dealbot does for its "Data Storage" check (e.g., how many datasets it creates per SP, what it asserts every run)
2. There is implementation that matches this documentation

Why Important

We've been talking/writing for a bit now about what Dealbot should be checking. We need to get that formalized in public documentation (that the dealbot UI can link to) so dealbot dashboard readers can understand the system and so engineers have a clear target of what to implement.

User/Customer

1. Dealbot maintainers
2. Dealbot dashboard consumers

Notes

1. Markdown in this repo is fine.
2. There is likely content from https://linear.app/filoz/project/robust-dealbot-user-provingexperience-fa6e2ea06a06/overview we can draw from.
3. Documentation should link to source code as the place for someone to see the source of truth