net-rs: add sample configs, document net-node in CLAUDE.md and README
Sample configs in net-node/configs/: - mainnet.toml: base config (mainnet magic, Leios enabled, production params, validation timing) - node0.toml: producer with 500/1000 stake, tx generation, file+log telemetry, peers to node1 - node1.toml: producer with 500/1000 stake, 50ms simulated delay on peer, file+log telemetry CLAUDE.md: add net-node testing section with usage examples, add net-node to workspace structure with module descriptions. README.md: add test node feature summary, add net-node to workspace structure, add test node usage section with two-node example, config layering explanation, and telemetry output format. Co-Authored-By: Claude Opus 4.6 (1M context) <[email protected]>