Design sketches

To do: backpressure-propagation
To do: canary-deployment-orchestrator
To do: dead-letter-reprocessing
To do: event-sourced-audit-log
To do: feature-flag-service
To do: multi-region-active-active
To do: observability-pipelines
To do: schema-registry-evolution
To do: tenant-isolation-multi-tenant
To do: zero-trust-audit-pipeline