Minimalistic solution for an offered coding challenge. A lot of shortcuts were taken, deliberately.
sbt run in a root directory launches web service, which binds to localhost:8080.
sbt test runs tests.
sbt assembly creates fat jar that could be launched via java -jar <path to jar>.
It's not stated what format should response have, so defaults are chosen (ie JSON of a required format for a specified error case, otherwise defaults for a http4s are used).
Functional tests are chosen over unit tests for a part of solution, cause I'm too lazy.
Logging is configured only for a console, with a minimal efforts.
Configuration is omitted deliberately.