Implement native BPMN workflows and guided modes

README.md

@@ -35,6 +35,14 @@ source path shown in the editor. Derivation copies an immutable graph revision
 and records its hash, node-library version, source scope, actor, Policy
 decision, and effective ancestor limits.
 
+BPMN 2.0 is Workflow's canonical graph language. The existing native graph
+editor models BPMN events, activities, gateways, data, collaborations, and
+artifacts directly; there is no separate modeler or browser-side BPMN library.
+XML import projects BPMN semantics and DI geometry into that graph, while XML
+export renders a deterministic interchange document from the graph. Immutable
+revisions pin both representations and the native profile version. Unsupported
+runtime semantics remain editable and portable, but activation fails closed.
+
 The start-node library distinguishes explicit user, API, scheduled, event, and
 parent-workflow starts. Manual starts and Dataflow/human handoffs are
 operational. The other trigger and generic capability nodes remain explicit
@@ -42,8 +50,5 @@ definition contracts until their event/schedule dispatchers and versioned
 operation providers are implemented.
 
 See [docs/CONCEPT.md](docs/CONCEPT.md) for the complete module concept.
-
-There is a BPMN component playing a major role here. Maybe this needs to
-become a separate module. It is quite viable to think about workflow
-modelling (and consequently import and export) in terms of BPMN, permitting
-a standardized configuration of the system.
+See [docs/BPMN_INTEROPERABILITY.md](docs/BPMN_INTEROPERABILITY.md) for the
+notation, conformance, and adapter boundary.