Handler contract that executes an ordered list of workflow steps after its bound channel delivers an event. Sequential Workflow is the standard coordination runtime for expressing document-owned logic without embedding host code. It reads the channelized payload, runs each step in order, records step results under step names when applicable, and returns processor effects such as patches, triggered events, explicit gas, or termination requests. The workflow is sequential: later steps can read earlier step results through `$steps` and can observe prior Update Document steps through the workflow's working document. The working document should be frozen/snapshot-backed and advanced by the same patch, conformance, dynamic generalization, and Type Generalization Policy rules that the Blue Contracts processor will use at commit time. This gives read-your-writes behavior without materializing the entire document as mutable state. Sequential Workflow does not weaken the Blue Contracts processor model. Patches are still applied through Update Document. Events are still emitted through Trigger Event or result emission. Boundary rules, reserved-key protection, post-patch type soundness, generalization, Document Update cascades, checkpoints, and gas accounting remain processor responsibilities. The workflow only provides a deterministic authoring/runtime structure for arranging these steps.