Update Network Config

Update configuration for a specific network.

Args: network_id: Network ID in format 'chain-network' (e.g., 'solana-mainnet-beta') config_updates: Dict with path-value pairs to update. Keys can be in snake_case (e.g., {"node_url": "https://..."}) or camelCase (e.g., {"nodeURL": "https://..."})

Example: POST /gateway/networks/solana-mainnet-beta