Comprehensive Architecture & Event-Driven Topology Diagram

CQRS & Request Pipeline

CommandBus and QueryBus build without DI containers via createCqrs()
Pipeline behaviors wrap handlers with validation, security, caching and telemetry
Symbol.for('@cqrs-ddd/request-kind') connects requests without coupling

Domain Events & Async Queues

Aggregates buffer domain events (UserCreatedEvent, UserUpdatedEvent, etc.)
CommandBaseHandler automatically publishes buffered events after successful persistence
BullMqUserEventDispatcher stamps tenant/correlation/principal using withJobContext()
Background workers drain queues under @InJobContext with complete execution context restored

Security & Multi-Tenancy Invariants

Fail-closed tenant schemas in PostgreSQL (no shared fallback)
Short-circuit cache and idempotency keys require tenant, principal and permissions
Version-conditioned optimistic updates (optimisticUpdate) eliminate lost updates