Replace jopt-simple with picocli

[cwperks]

Description

This change replaces JOpt Simple with picocli for command-line parsing in our application. The goals are:

• Modernise our CLI handling with a library that provides more advanced features, better maintenance, and a stronger ecosystem.
• Reduce risk associated with depending on a library that has seen very little activity in recent years.
• Align with current community practice and capabilities for parsing arguments (subcommands, annotation-based API, better help formatting, etc.).

jopt-simple was last released in 2017 and I think its time we move onto a dependency with more support.

Related Issues

Will open an issue to discuss the tradeoffs of these 2 CLI offerings. I see picocli as modernizing the application.

Check List

• Functionality includes testing.
• API changes companion pull request created, if applicable.
• Public documentation issue/PR created, if applicable.

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[github-actions]

❌ Gradle check result for 77df622:

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[github-actions]

❌ Gradle check result for 77df622: FAILURE

Please examine the workflow log, locate, and copy-paste the failure(s) below, then iterate to green. Is the failure a flaky test unrelated to your change?