- Add p2p_node_id field to ChainSettings with empty string default
- Add p2p_node_id to .env.example configuration file
- Change --node-id argument from required to optional with default empty string
- Add node_id resolution with fallback chain: args.node_id -> settings.p2p_node_id -> settings.proposer_id
- Add validation to raise ValueError if no node_id can be resolved
- Update systemd service to use ${