Fix artifact selection when repository name casing differs

[aaryan-iiitu]

Context

While looking into issue #1576, I noticed that Scaladex can end up selecting an outdated artifact when the repository name and the artifact name differ only by casing (for example, ScalaFX vs scalafx). This happens because artifact selection currently relies on case sensitive string comparisons and case sensitive alphabetical ordering.

What this PR changes

• Compare repository names and artifact names in a case-insensitive way
• Make alphabetical ordering of artifact names case insensitive as well
• Add a regression test to ensure this behavior doesn’t break again

Why this approach

The existing selection rules and priority order are kept exactly the same. This change only normalizes string comparisons so that casing differences don’t affect which artifact is selected.

Verification

• Added a test that reproduces the issue
• Ran the full coreJVM/test suite locally; all tests pass