Add global config validation

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What's the problem

There are some config combinations that are invalid.

For example, the following config:

if (!config.enableRecursiveGateways && !config.enableGatewayProviders && !config.enableWss && !config.enableWebTransport) {
    // crude validation
    throw new Error('Config is invalid. At least one of the following must be enabled: recursive gateways, gateway providers, wss, or webtransport.')
  }

Suggestion solution

Add global validation to the config component, that runs on the saveConfig.