Code-gov Improvements: Agency Cards and Tests

## MENTOR
- @natalialuzuriaga, @decause-gov
- Software Engineer, CMS OSPO, code-gov inventory
- #dsac-ospo on Slack

## BRIEF DESCRIPTION

### Backend
The backend is powered by scripts triggered by GitHub Actions: https://github.com/DSACMS/code-gov/tree/main/scripts. Currently, these scripts are failing: https://github.com/DSACMS/code-gov/actions/runs/29187121813/job/86635160396. Please review the code and its functionality, and see whether it is still fetching and creating the agency-index files: https://github.com/DSACMS/code-gov/tree/main/agency-indexes. Write unit tests to ensure it is working.

### Frontend
We would like to add the following information for each agency card in the agencies tab:
- `code.json: placeholder` should be a link to the agency's agency-index.json found in https://github.com/DSACMS/code-gov/tree/main/agency-indexes
- Ensure that `projects: ##` count is correct
- Include a full name and description of the agency in its agency card

## SCOPING
- 2-3 days

## SKILLS NEEDED
Full Stack, Documentation, Metadata, Testing

## REQUIRED DELIVERABLES
1. Review backend. Create unit tests to ensure functionality. Write docs explaining data fetching and processing

2. Each agency card should have:
- Link to code.json link
- Project count
- Agency full name
- Description

## NOTES/INSPO
Review with Remy on any other information to be added to code-gov!

# ACKNOWLEDGEMENTS
- [X] - Yes, I agree to spend file a project proposal ticket
- [x] - Yes, I agree this project falls within a 2 week or less (ideally less) scope of time
- [x] - Yes, I agree to spend an hour per week of office hours and 1x1 mentoring
- [x] - Yes, I agree to spend an hour at the end of the sprint for filling out a Retro Template

Start with the failing GitHub Actions run and review the scripts directory to determine whether agency-index files are still fetched and created. Inspect the agency-indexes directory and the agencies tab implementation before adding unit tests and documentation. Done means backend tests pass, data processing is documented, and each agency card links to its agency-index.json and shows the correct project count, full name, and description.

Written by the indexing model from the issue text.