Release all reactor libraries from the tag-driven release

[simbo1905]

Problem

The tag-driven release publishes only part of the reactor. The json-java21-jtd-codegen and jtd2jar modules are attached to the jtd-codegen Maven profile, which activates on JDK 24+ (ClassFile API, JEP 484). The release workflow deploys on JDK 21, so those two modules never enter the reactor and are never published. Release 2026.08.30 delivered 6 of 8 artifacts to Maven Central (java.util.json.jtd.codegen and jdt2jar return 404 on repo1.maven.org), and the GitHub Release notes / README advertise only the core jar and the Docker image.

Fix

• Bump the release workflow (release-on-tag.yml) deploy step from JDK 21 to JDK 25 so the JDK-24+ profile activates and mvn -P release clean deploy publishes json-java21-jtd-codegen and jtd2jar alongside everything else. CI already runs a Java 25 job, so these modules are exercised on 25 daily.
• Extend the GitHub Release body with an explicit artifacts section listing every published Maven coordinate (io.github.simbo1905.json: java.util.json, java.util.json.jsonpath, java.util.json.jtd, java.util.json.jtd.codegen, json-compatibility-suite, json-java21-api-tracker, jtd2jar) plus the GHCR jtd2jar image.
• Add a "Published Artifacts" section to README.md listing the same coordinates so the standing documentation matches what a release delivers.

Why

Users of the JTD tooling cannot find jtd-codegen/jtd2jar on Central; the release page undersells what is shipped. The deploy step is the only place where JDK 21 vs 25 matters for publishing.