Creates the skeleton observability stack (no running services yet) that all
subsequent Grafana LGTM + GlitchTip issues depend on:
- docker-compose.observability.yml: external archiv-net join, obs-net bridge,
named volumes for all five services, placeholder comments for each service
group (Metrics/Logs/Traces/Dashboards/Error Tracking), startup-order note
- infra/observability/{prometheus,loki,promtail,tempo,grafana/provisioning/{datasources,dashboards}}/.gitkeep
- .env.example: new # --- Observability --- section with PORT_GRAFANA,
PORT_GLITCHTIP, PORT_PROMETHEUS, GLITCHTIP_DOMAIN, GLITCHTIP_SECRET_KEY
(with generation hint), SENTRY_DSN, VITE_SENTRY_DSN
Verified: docker compose -f docker-compose.observability.yml config exits 0
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
