Build and deploy a Twitch Extension with a configuration service and backend messaging

Steps

1. Create the extension in the Twitch Developer Console (dev.twitch.tv/console), choosing its type (panel, overlay, or component) and generating its shared secret
2. Implement the frontend using twitch-ext.min.js to receive the JWT-authenticated context and bootstrap configuration
3. Use the Extension Configuration Service to store Developer, Broadcaster, and Global segments, keeping in mind that Global/Broadcaster segment data delivered to the frontend is effectively public and unauthenticated on read
4. Send real-time updates to viewers with the Send Extension PubSub Message endpoint, authenticating backend calls with a JWT signed by the extension's shared secret using the 'external' role
5. Respect the Extension PubSub limits of one message per second per channel and a 5 KB max payload per message
6. Submit the extension for Twitch review before making it available to broadcasters, and rotate secrets carefully since an old secret only stays valid for about an hour after a new one is generated