Collect KurrentDB version from the info endpoint on registration #759

Goal\nCollect the KurrentDB version when registering a KurrentDB monitor and store it as the service version shown in the Health Monitoring UI.\n\n## Requirements\n- Query the KurrentDB info endpoint during registration.\n- Extract and normalize the server version into a concise human-readable value.\n- Persist the result in the registered service version field.\n- Preserve registration behavior when the info endpoint is unavailable or does not expose a usable version; record a clear fallback or leave the version unavailable without failing an otherwise valid registration.\n- Add automated coverage for the endpoint response, parsing, and registration behavior.\n\nRelated: #757