03-observability-and-apm

Lessons in this module:

• 01-structured-logging-and-sentry — Structured JSON Logging, Correlation IDs & Sentry Triage
• 02-prometheus-and-grafana — Prometheus Metrics (RED/USE), PromQL & Grafana Dashboards
• 03-distributed-tracing-and-apm — OpenTelemetry Distributed Tracing & Flamegraph Profiling