CC-2002: Upgrade Java to 25

[andy1li]

Note

Upgrades Java to 25 across starters/solutions, enables preview features, and adds a Java 25 Dockerfile.

• Java upgrade
  • Switch buildpack to java-25 in compiled_starters/java/codecrafters.yml and solutions/java/01-vi6/code/codecrafters.yml.
  • Add dockerfiles/java-25.Dockerfile using eclipse-temurin-25.
• Runtime changes
  • Run scripts updated to use java --enable-preview in *.codecrafters/run.sh and your_program.sh across starters/solutions/templates.
• Build config (Maven)
  • Update pom.xml in compiled_starters/java, solutions/java/01-vi6/code, and starter_templates/java/code:
    • Set maven.compiler.source/target and java.version to 25.
    • Add maven-compiler-plugin --enable-preview compiler arg.

^{Written by Cursor Bugbot for commit f4abded. This will update automatically on new commits. Configure here.}

[linear]

CC-2002 Upgrade Java to 25