Workflow runtime core: plan model, DSL, registry, public WorkflowOperations facade, generic transactional SPIs, side-effect recorder SPI, contract annotations. SQL-free.

Workflow services integration: outbox-backed SERVICE side-effect recorder and inbox-deduplicated signal contributor.

Workflow events module: durable workflow event stream via outbox-backed WORKFLOW_EVENT side-effect recorder.

PostgreSQL persistence for workflow state machines: instance/history/dedup repositories, PgWorkflowEngine, optimistic concurrency, Flyway migrations.

Annotation processor that generates static {Contract}_WorkflowClientProxy classes and a GeneratedWorkflowClientsModule for @WorkflowContract interfaces, replacing the per-call JDK dynamic proxy, plus compile-time contract-shape validation

Portable, dialect-neutral workflow orchestration runtime: SPI-driven execution kernel decoupled from any SQL dialect or persistence backend.

Source-agnostic declarative workflow definitions: YAML/JSON documents compiled to the canonical WorkflowPlan via the existing WorkflowBuilder. Replaceable expression profile (CEL candidate) for safe routing.

Workflow timers and signal-wait timeouts: transactional delayed-job enqueue, source-of-truth timer table, orphan and dead-letter recovery.

Human task action APIs: TaskService (list/get/complete/reassign), typed-per-decision payload binding, idempotent commands with WorkflowActor audit identity. Cycle-2 timer reuse for due-dates.