XLayer migrated from Polygon CDK to OP Stack (Jovian fork, Oct 2025). The Kafka-based [Eth.GPO.XLayer] section was removed in op-geth v0.1.4 (okx/op-geth PR #168, Feb 2026) and causes Fatal crash on startup. Replace with standard OP Stack GPO config with MinSuggestedPriorityFee. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>