Build and host a flagship demo: real-time dashboard (K8s pod monitor or live chat)

[mirkobrombin]

The counter example doesn't sell SSC. We need a demo that shows what rfw is uniquely good at: live data over WebSocket, Go end-to-end.

Candidates:

• Real-time Kubernetes pod monitor (200 lines of Go, talks to k8s API, live table of pods with status)
• Live chat with multiple browser tabs (shows WebSocket broadcast)
• Observability panel with Prometheus metrics streamed live

Host it on Fly.io (free tier works). Link it from README hero section. Ship a companion "build this in 30 min" tutorial.

This is the proof the ICP needs: "I can build my internal tool in pure Go, no JS, and it updates live."