Api tests

[kjdiaz508]

Developer: Kevin Diaz

Closes #46

Pull Request Summary

Adds Jest-based API tests for the recipes endpoints using an in-memory MongoDB.
Covers GET, POST, PATCH, and DELETE behavior, including pagination, filtering, validation errors, and not-found cases.

Also fixes a bug in POST endpoint (try/catch was not surrounding anything).

Modifications

• __tests__: various tests for the API endpoints.

Testing Considerations

{list out what you have tested and what the reviewer should verify}

Pull Request Checklist

• Code is neat, readable, and works
• Comments are appropriate
• The commit messages follows our guidelines
• The developer name is specified
• The summary is completed
• Assign reviewers

Screenshots/Screencast

{put screenshots of your change, or even better a screencast displaying the functionality}

[soramicha]

Looks great, code is structured in a neat and organized way, thanks Kevin!