T09: KI-Copilot API + Hybrid Workflow Engine + LLM client + event-triggered workflows

- KI-Copilot: NL query → proposed actions, execute with RBAC, history, audit logging
- LLM client: mock mode (no API key) + OpenAI-compatible mode (AI_MODEL/AI_API_KEY)
- Action mapper: NL intent → API calls (create/update/delete/search company/contact)
- Workflow engine: step types (action/approval/notification/condition), JSONB steps
- Workflow lifecycle: pending → in_progress → completed/rejected/cancelled
- Event-triggered workflows: event bus → auto-start instances
- Code-engine workflows: onboarding on user.created event
- Approval timeout: auto-reject after configured hours
- 5 new tenant-scoped tables with RLS: ai_conversations, ai_messages, workflows, workflow_instances, workflow_step_history
- Migration 0004: all tables + RLS policies + tenant_id + indexes
- 238 tests pass (30 AC + 105 coverage + 103 existing), 84.12% T09 module coverage
- MissingGreenlet fix: safe accessor helpers for async ORM attribute access

app/core/event_bus.py

@@ -39,3 +39,13 @@ _event_bus = EventBus()
 def get_event_bus() -> EventBus:
     """Get the global event bus."""
     return _event_bus
+
+
+def register_workflow_event_handlers() -> None:
+    """Register workflow event handlers on the global event bus.
+
+    Subscribes to events that can trigger workflows (user.created, etc.).
+    Should be called during application startup.
+    """
+    from app.workflows.engine import register_workflow_event_handlers as _register
+    _register()