Validate BPMN export in real BPMN tools

[DKFuH]

We need a contributor to sanity-check the BPMN skeleton export in real BPMN tooling.\n\nScope\n- Run orgscript export bpmn on at least 1-2 examples (e.g. examples/craft-business-lead-to-order.orgs).\n- Import the output into a BPMN editor (Camunda Modeler, bpmn.io, etc.).\n- Confirm the XML loads and the diagram layout renders (BPMN DI is included).\n- Report any import warnings, missing nodes, or layout issues with screenshots/logs if possible.\n\nNotes\n- This exporter is marked experimental/skeleton.\n- We only expect process blocks to export.\n\nDeliverable\n- Short report in the issue with the tool used, steps, and findings.