Counties table cleaning + population update

[josh-chamberlain]

Context

There's an official source for U.S. Counties, with FIPS codes and population.

We can use the FIPS codes to make sure our counties

• Structure: https://www.census.gov/data/datasets/2024/econ/gus/public-use-files.html
• Population: https://www.census.gov/data/datasets/time-series/demo/popest/2020s-counties-total.html

Requirements

• surface discrepancies in our counties table
  • are there counties our db is missing, or that have incorrect metadata?
  • are there counties our db has that aren't in the new data?
• resolve discrepancies
  • "how" depends on what the discrepancies look like
  • removing counties will result in agencies without counties; we will need to resolve those too
• add a population for counties
  • use the most recent estimates. This will help us prioritize search results and report out metrics—what percentage of the U.S. population are we covering, for example?