Migrate publishing to new Maven Central Portal with vanniktech plugin

[Copilot]

Replace legacy Sonatype OSSRH publishing setup with new Maven Central Portal using vanniktech maven publish plugin.

Build Configuration

• Replace manual maven-publish, signing, and nexus-publish plugins with vanniktech-maven-publish v0.34.0
• Simplify publishing configuration from 75 lines of manual setup to 39-line declarative block
• Retain all POM metadata (organization, licenses, developers, SCM)

Release Workflow

• Update environment variables to vanniktech conventions:
  • OSS_USER/OSS_PASS → ORG_GRADLE_PROJECT_mavenCentralUsername/Password
  • SIGNING_KEY/PASS → ORG_GRADLE_PROJECT_signingInMemoryKey/Password
• Replace publishToSonatype closeAndReleaseSonatypeStagingRepository with publishToMavenCentral

The plugin automatically handles javadoc/sources jar generation, signing, and staging for Kotlin multiplatform projects. Existing GitHub secrets work without modification via Gradle's ORG_GRADLE_PROJECT_ prefix mapping.

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

• download.jetbrains.com
  • Triggering command: /usr/lib/jvm/temurin-17-jdk-amd64/bin/java --add-opens=java.base/java.lang=ALL-UNNAMED --add-opens=java.base/java.lang.invoke=ALL-UNNAMED --add-opens=java.base/java.util=ALL-UNNAMED --add-opens=java.prefs/java.util.prefs=ALL-UNNAMED --add-exports=jdk.compiler/com.sun.tools.javac.api=ALL-UNNAMED --add-exports=jdk.compiler/com.sun.tools.javac.util=ALL-UNNAMED --add-opens=java.base/java.util=ALL-UNNAMED --add-opens=java.prefs/java.util.prefs=ALL-UNNAMED --add-opens=java.base/java.nio.charset=ALL-UNNAMED --add-opens=java.base/java.net=ALL-UNNAMED --add-opens=java.base/java.util.concurrent=ALL-UNNAMED --add-opens=java.base/java.util.concurrent.atomic=ALL-UNNAMED --add-opens=java.xml/javax.xml.namespace=ALL-UNNAMED --add-opens=java.base/java.time=ALL-UNNAMED -Xmx700m -Dfile.encoding=UTF-8 -Duser.country -Duser.language=en -Duser.variant -cp /home/REDACTED/.gradle/wrapper/dists/gradle-9.1.0-bin/9agqghryom9wkf8r80qlhnts3/gradle-9.1.0/lib/gradle-daemon-main-9.1.0.jar -javaagent:/home/REDACTED/.gradle/wrapper/dists/gradle-9.1.0-bin/9agqghryom9wkf8r80qlhnts3/gradle-9.1.0/lib/agents/gradle-instrumentation-agent-9.1.0.jar org.gradle.launcher.daemon.bootstrap.GradleDaemon 9.1.0 (dns block)
• vanniktech.github.io
  • Triggering command: curl -s REDACTED (dns block)

If you need me to access, download, or install something from one of these locations, you can either:

• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
• Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)

Original prompt

---

This section details on the original issue you should resolve

<issue_title>Migrate publishing to new maven central</issue_title>
<issue_description>Things needed:

• adjust gradle build configuration
• adjust the release github workflow

The inspiration could be taken from how it is done in https://github.com/Smarteon/loxone-java

• https://github.com/Smarteon/loxone-java/blob/master/build.gradle.kts - note the vanniktech maven publish
• https://github.com/Smarteon/loxone-java/blob/master/.github/workflows/loxone-java-release.yml

However this project is kotlin multiplatform, so studying the documentation for publishing plugin is wise.

The secrets and variables are already ready in github.</issue_description>

<agent_instructions>Please do not make excessive commenting in the code.</agent_instructions>

Comments on the Issue (you are @copilot in this section)

• Fixes Migrate publishing to new maven central #61

---

✨ Let Copilot coding agent set things up for you — coding agent works faster and does higher quality work when set up for your repo.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 61.79%. Comparing base (d76fd5a) to head (e5ef9db).
⚠️ Report is 6 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master      #62   +/-   ##
=======================================
  Coverage   61.79%   61.79%           
=======================================
  Files          22       22           
  Lines         458      458           
  Branches       93       93           
=======================================
  Hits          283      283           
  Misses        107      107           
  Partials       68       68           

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.