Jira ticket

RUN-4639

Description

org.rundeck is over Maven Central's free publishing limits (RUN-4570); Sonatype begins rate-limiting publishing on 2026-08-11. This applies the same PackageCloud migration already validated end-to-end on the rundeck-plugins org repos (RUN-4638) to this repo's 3 Maven modules: rd-api-client, rd-cli-lib, and rd-cli-tool.

• Removes the nexus-publish plugin and nexusPublishing {} block.
• Registers PackageCloud (https://packagecloud.io/pagerduty/rundeck/maven2) as the publishing repository in gradle/publishing.gradle, reusing the same PackageCloud repo the CLI's .deb/.rpm already publish to — no new PackageCloud repo needed.
• Signs artifacts with the gpg CLI and uploads signatures via curl in release.yml, instead of Gradle's signing plugin: Gradle auto-generates a checksum for every publication artifact including .asc files, and PackageCloud's Maven endpoint 422s on the checksum-of-a-signature-file, aborting the publish task partway through.
• rd-cli-tool sets archivesBaseName='rundeck-cli', so its local build output filenames (rundeck-cli-<version>*.jar) differ from its published Maven artifactId (rd-cli-tool) — the signing step signs the local files but uploads the .asc under the published coordinate name.

Existing versions already published on Maven Central are unaffected — only future releases move to PackageCloud only. The GitHub Release step and the existing .deb/.rpm PackageCloud push are untouched.

Testing instructions

• ./gradlew clean build passes locally with all tests (verified: BUILD SUCCESSFUL, 75 tasks, all 3 modules + integration-tests).
• ./gradlew tasks --all confirms publishAllPublicationsToPackageCloudRepository exists for rd-api-client, rd-cli-lib, and rd-cli-tool.
• ./gradlew build still succeeds with no PKGCLD_REPO_URL/PKGCLD_WRITE_TOKEN set (the gradle.yml CI workflow is unaffected — the fallback default in publishing.gradle avoids a null-URL crash).
• To fully verify: push a test tag to trigger release.yml, confirm the 3 artifacts (plus -sources/-javadoc, and rd-cli-tool's -all jar) and their .asc signatures land under https://packagecloud.io/pagerduty/rundeck/maven2/org/rundeck/..., and confirm PKGCLD_WRITE_TOKEN/SIGNING_KEY_B64/SIGNING_PASSWORD secrets are available to this workflow.