[hippi345]

Summary

One PR for the Dependabot bumps that stay on JDK 21 and pass mvn -B spotless:check test (5 tests, 0 failures) with the current compiler and Surefire plugins. The repository default branch is master (there is no main).

Dependabot groups: now batches future minor and patch updates for Maven and GitHub Actions. Major updates stay as their own PRs.

Supersedes

These open Dependabot PRs are covered here. They are left open.

PR	Bump
#37	com.diffplug.spotless:spotless-maven-plugin 2.43.0 → 3.10.4
#35	org.junit.jupiter:junit-jupiter 5.11.4 → 6.1.3
#32	actions/setup-java v5 → v6
#30	actions/checkout v4 → v7

Spotless 3 only requires Java 17. The existing googleJavaFormat 1.23.0 / removeUnusedImports config is unchanged, and spotless:check is clean. JUnit 6 needs Java 17 and Surefire 3.0.0+; tests use @Test and assertions only, and they pass on Surefire 3.5.2. The workflow uses pull_request (not pull_request_target) with distribution: temurin, so checkout v7 and setup-java v6 are drop-in tag bumps.

Left out

PR	Bump	Reason
#38	org.openjfx:javafx-controls 21.0.6 → 27.0.1	JavaFX 27 is compiled with --release 25 and requires JDK 25 or later (JDK-8376601). This repo’s compiler release, CI job, and README are JDK 21. Taking the bump is a JDK migration, not a version-only change.
#34	maven-compiler-plugin 3.13.0 → 3.16.0	Skipped on purpose. Joel is merging this himself.
#31	maven-surefire-plugin 3.5.2 → 3.6.0	Skipped on purpose. Joel is merging this himself.

Test plan

• mvn -B spotless:check test on JDK 21 — BUILD SUCCESS, Tests run: 5, Failures: 0, Errors: 0
• GitHub Actions CI on this PR (spotless:check, compile, test)