Add better error handling

[Karolina-Bogacka]

Issue: #25
Adds error handling. Deletes the Fool Around command as well - seems redundant.

Tested on AOT generated locally, but encountered some warnings that were not there when I ran the tests - I'll test it on AOT generated through the github workflow in a minute and let you know.

[Karolina-Bogacka]

Tested on AOT from github workflow, no warnings here, it must be a local generation issue then.

[Ostrzyciel]

Tested on AOT from github workflow, no warnings here, it must be a local generation issue then.

Could you specify what warning is this and what Graal version you have? If it appears on a newer version of Graal, then it will eventually appear in CI. It's worth opening an issue to resolve this.

[Karolina-Bogacka]

Warning text:

WARNING: A terminally deprecated method in sun.misc.Unsafe has been called
WARNING: sun.misc.Unsafe::objectFieldOffset has been called by scala.runtime.LazyVals$ (file:/home/karokaro/IdeaProjects/cli/target/graalvm-native-image/jelly-cli)
WARNING: Please consider reporting this to the maintainers of class scala.runtime.LazyVals$
WARNING: sun.misc.Unsafe::objectFieldOffset will be removed in a future release

native-image --version

native-image 24 2025-03-18
GraalVM Runtime Environment Oracle GraalVM 24+36.1 (build 24+36-jvmci-b01)
Substrate VM Oracle GraalVM 24+36.1 (build 24+36, serial gc, compressed references)

[Karolina-Bogacka]

Tested on AOT and works. Test coverage for methods generally above 80%, most but not every custom exception currently included in test - if needed, more mocks will be added.

[Karolina-Bogacka]

Corrected comments, checked AOT/tests, everything still works