refactored health

app/routers/health.py

@@ -31,7 +31,7 @@ from app.service.llm_service import LocalLLMService, get_llm_service
 from app.tasks.analytics_worker import get_worker_manager
 from app.service.vector_service import VectorService
 from app.mapper import health_check_mapper, MapperMetrics
-from app.core.event_hub import  StreamingResponse, Response
+from fastapi.responses import StreamingResponse, Response
 from app.core.sre_logging import log_aggregator, emit_worker_log, emit_vector_log, emit_llm_log, emit_mapper_log, emit_deps_log
 
 # Prometheus aggregation