Build 1.0.0-SNAPSHOT outside releases - #29

Summary

• gradle.properties: the version becomes 1.0.0-SNAPSHOT, so a local build and its locally published snapshot can never be mistaken for the 1.0.0 release.
• build-and-verify.yml: the version input defaulted to 1.0.0 and was passed to Gradle as ORG_GRADLE_PROJECT_version. That overrode gradle.properties in every CI build, so CI built 1.0.0 artifacts. Now:
  • The input defaults to empty.
  • A first step in both jobs exports ORG_GRADLE_PROJECT_version only when a version is passed, which only the release workflow does. An empty variable would give Gradle an empty version.
  • CI builds now use the snapshot version, and a release tag still builds its own version.
• jonoffcpu-agent/README.md: the Maven coordinates, the build output path and the -javaagent example refer to the version in gradle.properties instead of hardcoding 1.0.0.

Nothing else hardcodes the version:

• CI's packaging step matches jonoffcpu-agent-*.jar and excludes the -plain JARs.
• The release jobs pass the tag's version explicitly.
• The root README shows only released versions, which the release workflow updates.

Verification

• ./gradlew spotlessCheck :jonoffcpu-agent:check :jonoffcpu-correlator:check :jonoffcpu-jfr-converter:check :jonoffcpu-capture-codec:check passes and produces jonoffcpu-*-1.0.0-SNAPSHOT.jar.
• actionlint and zizmor (online audits) report no findings.