feat(demo): Grafana + OTel Collector docker-compose demo

[brucearctor]

Summary

Ship a docker-compose demo that lets users see UserALE behavioral data in Grafana in under 5 minutes.

Components

# example/otel-demo/docker-compose.yml
services:
  collector:     # OTel Collector with OTLP receiver
  grafana:       # Grafana with pre-provisioned dashboard
  loki:          # Log storage backend
  example-app:   # Example page with UserALE + OTLP exporter

Pre-built Grafana Dashboard

• Event timeline (clicks, scrolls, keystrokes over time)
• Session heatmap (events by session)
• Top interaction targets (most-clicked elements)
• User flow (page URL transitions)
• Event type distribution

First-run Experience

cd example/otel-demo
docker-compose up
open http://localhost:8080   # Example app
open http://localhost:3000   # Grafana dashboard

Depends On

• feat(export): OTLP/JSON exporter for OpenTelemetry integration #140 (OTLP exporter)