- _build_procedural_tree now maps AI node types (step, action, warning) to
valid procedural types (procedure_step, section_header, procedure_end)
- Generates 'title' field from content text — fixes "Unnamed step" in editor
- Auto-appends procedure_end step if AI didn't generate one
- Adds procedural validation gate at commit endpoint (same as troubleshooting)
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>