feat: add marketplace metrics, privacy features, and service registry endpoints

- Add Prometheus metrics for marketplace API throughput and error rates with new dashboard panels
- Implement confidential transaction models with encryption support and access control
- Add key management system with registration, rotation, and audit logging
- Create services and registry routers for service discovery and management
- Integrate ZK proof generation for privacy-preserving receipts
- Add metrics instru

enterprise-connectors/python-sdk/aitbc_enterprise/erp/sap.py

@@ -0,0 +1,19 @@
+"""
+SAP ERP connector for AITBC Enterprise (Placeholder)
+"""
+
+from .base import ERPConnector, ERPSystem, Protocol
+
+
+class SAPConnector(ERPConnector):
+    """SAP ERP connector with IDOC and BAPI support"""
+    
+    def __init__(self, client, config, sap_client):
+        # TODO: Implement SAP connector
+        raise NotImplementedError("SAP connector not yet implemented")
+    
+    # TODO: Implement SAP-specific methods
+    # - IDOC processing
+    # - BAPI calls
+    # - SAP authentication
+    # - Data mapping for SAP structures