fix: restore hermetic Java SDK verification baseline

[josedab]

Summary

• Separates unit/integration Maven lifecycles, repairs examples and Spring optional beans, and bounds external integration selection.
• Preserves repository public contracts while restoring or strengthening the verification baseline.
• Includes an AUDIT.md where the repository reached the audit/refactor phase.

Commits

• abc4582 fix(java): restore hermetic Maven verification baseline
• 8fbef60 docs(java): record clean-code audit

Validation

mvn clean verify passes with 336 unit tests; 58 external ITs are explicitly gated.

Known blockers / deferred work

• None beyond required PR checks and documented AUDIT.md deferrals.

Merge readiness

Ready for review. Merge only after all required GitHub checks and reviewer approvals pass.