[Quality] Bind CDC bootstrap API and public documentation

[seonghobae]

Quality / acquisition gap

Protected develop@622e5e6c3d534f230c390f10e3832efadfc01825 contains an independently runnable CdcApplication with @SpringBootApplication, @EnableDiscoveryClient, @EnableKafka, and configuration-properties enablement, but the public bootstrap class and main(String[]) entry point have no beginner-readable Javadoc and no focused bootstrap contract.

This issue is path-disjoint from active CDC acknowledgement/lifecycle/replication/value-object work. It must not change Kafka delivery semantics, CDC source/target registries, replication, configuration values, dependencies, or runtime credentials.

RCA

• Immediate cause: public bootstrap class/method are undocumented.
• Technical cause: startup annotation identity and public entrypoint documentation are not enforced locally.
• Control gap: broad repository coverage/docstring issue [Quality evidence] Extend non-vacuous 100% coverage to every owned production module #205 is not a substitute for a focused production bootstrap boundary.

TDD / acceptance

1. Add a focused test first preserving @SpringBootApplication, @EnableDiscoveryClient, @EnableKafka, and public-static main(String[]).
2. Require beginner-readable class/method Javadoc explaining standalone mightyETL CDC startup, discovery/Kafka bootstrap responsibilities, and args.
3. Observe hosted RED exactly at missing Javadoc after successful production/test compilation; setup/import/dependency failure is not valid RED.
4. Apply Javadoc-only GREEN; preserve annotations and SpringApplication.run(...) behavior.
5. Run full applicable CI/dependency/SBOM/SAST/security evidence.
6. Keep exact-source, scanner-completeness, selected/repository-wide coverage and merge-governance controls independent.