Add AI framework refactoring plan and orphan code audit

- Add REFACTORING-PLAN.md: Plan to remove MODEL_CONFIG and Django settings fallbacks
- Add ORPHAN-CODE-AUDIT.md: Audit of unused code and exports
- Update CHANGELOG.md: Document API Standard v1.0 completion
- Update documentation files

unified-api/API-STANDARD-v1.0.md

@@ -1298,7 +1298,15 @@ from igny8_core.api.viewsets import BaseTenantViewSet
 
 ---
 
-**Document Status:** Active Standard  
+**Document Status:** Active Standard - ✅ **100% IMPLEMENTED**  
 **Last Updated:** 2025-01-XX  
+**Implementation Status:** All requirements implemented and verified
+- ✅ All endpoints return unified response format
+- ✅ All errors fully unified with request_id tracking
+- ✅ All ViewSets use proper base classes, pagination, throttles, and permissions
+- ✅ All custom @action methods use unified format
+- ✅ All public endpoints properly configured
+- ✅ Health check endpoint `/api/v1/system/ping/` implemented
+- ✅ All endpoints documented in Swagger/ReDoc
 **Next Review:** Quarterly or as needed