Add ConfigV3 env parsing support

[mageddo]

Summary

• add the ConfigV3 data model together with JSON, YAML and env converters
• implement EnvConverter so DPS_* env vars are mapped into ConfigV3
• provide sample ConfigV3 template fixtures and unit tests
• add jackson-dataformat-yaml dependency and a basic YamlUtils helper

Testing

• ./gradlew test (fails: CircuitBreakerDelegateSelfObservableTest.mustHalfOpenCircuitAfterConfiguredTimeAndSatisfyHealthCheck, NetExecutorWatchdogTest.mustCancelPingWhenFutureGetsDoneFirst)

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https://chatgpt.com/codex/tasks/task_e_68d159e2cbdc832aac90fdf2fc1c8e54