fix(release): verify public candidates and prepare 0.2.3 development

[ChoMinGi]

What changed

Central publication completed after the initial ten-minute polling deadline, and resuming the old check rejected its published-coordinate response. Keep strict coordinate checks before publishing, verify published parent/module identities through unauthenticated public POMs, and allow thirty minutes for synchronization. Existing candidates are never rebuilt or uploaded again.

Prepare 0.2.3-SNAPSHOT, advance API compatibility to published 0.2.2, and preserve the exact release's hosted two-hour evidence and public-consumer audit. README installation versions remain 0.2.2. No runtime source changes or tag changes.

Testing

• Publication state tests: validated, qualified PURLs, published without validation-time PURLs, wrong coordinates, wrong deployment, failed state and wrong public POM; verify no Central authorization is forwarded to the public repository.
• actionlint and whitespace checks pass.
• Maven Central 0.2.2 resolved into a fresh cache; Spring AI (2), LangChain4j (2) and explicit observation (5) consumer tests pass.
• Public core JAR SHA-256 exactly matches the successful hosted two-hour test JAR. Release CI and hosted soak links are in RELEASE-0.2.2.md.
• Hosted CI validates the new development version and 0.2.2 API baseline before merge.

Checklist

• Public consumers verified independently of a reactor install
• Publication checks exercised with success and rejection cases
• Release provenance and limitations documented
• No credentials or model data included