Rewrite maifetch in Kotlin

[BowenMilner]

Summary

• Rewrites the maifetch CLI and MaiTea API wrapper from Go to Kotlin/JVM.
• Preserves the access token/config/env/CLI precedence, score-count cap, default config path behavior, recent plays fetch, profile output, ANSI score formatting, and optional ASCII logo output.
• Adds Gradle build configuration, focused Kotlin tests, and GitHub Actions CI for Java 17 + Gradle.

Validation

• git diff --check
• rg -n "[^[:ascii:]]" . returned no matches
• Local gradle test could not be run because this environment has no Java runtime or Gradle installed; CI is included so the PR receives a real build/test signal on GitHub.

/claim #1

[BowenMilner]

Fork CI is green for this branch:
https://github.com/BowenMilner/maifetch/actions/runs/27275843502

The run completed gradle test successfully on Java 17 / Gradle 8.14.3.