495c000356
Create packages/workflow-runtime with the minimal runtime subset: - Types (WorkflowFn, RoleOutput, AgentBinding, etc.) - createWorkflow (pure orchestration, zero I/O) - validateWorkflowDescriptor - Result/ok/err, START/END constants Zero external dependencies (zod as peer only). Zero node:fs/node:path imports. Engine (@uncaged/workflow) now depends on workflow-runtime and provides CAS/merkle/extract implementations via injection. Refs #121, relates #122