Elsa.Bpmn.Activities.BpmnProcess completed with the interpreter's Done or
Cancelled outcome but declared no outcomes, so a Flowchart composing it only
saw Studio's synthesized default port and the Cancelled outcome was
unreachable. Declares both via [FlowNode(BpmnInterpreter.DoneOutcomeName,
BpmnInterpreter.CancelledOutcomeName)] (both const in Bpmn.Semantics 0.2.0),
adds a descriptor test asserting the two flow ports, and a composition test
routing a cancelled transaction down the Cancelled port.
Co-authored-by: Claude Opus 5 <noreply@anthropic.com>
