Configure Sonatype Central publishing

[rhoegg]

Summary

• Configured central-publishing-maven-plugin for Sonatype Central deployment
• Disabled standard maven-deploy-plugin to prevent conflicts with parent POM
• Updated GitHub Actions workflow with Central credentials

Changes

• Sonatype Central publishing configuration
• GitHub Actions workflow for manual release trigger

Test plan

• Local signing works with GPG
• Local deployment to Central works
• GitHub Actions workflow executes successfully