Add POI feature and imporve the overall backend implementation

services/pos/app/main.py

@@ -89,11 +89,28 @@ class POSService(StandardFastAPIService):
 
     async def on_startup(self, app: FastAPI):
         """Custom startup logic for POS service"""
+        # Start background scheduler for POS-to-Sales sync
+        try:
+            from app.scheduler import start_scheduler
+            start_scheduler()
+            self.logger.info("Background scheduler started successfully")
+        except Exception as e:
+            self.logger.error(f"Failed to start background scheduler: {e}", exc_info=True)
+            # Don't fail startup if scheduler fails
+
         # Custom startup completed
         self.logger.info("POS Integration Service started successfully")
 
     async def on_shutdown(self, app: FastAPI):
         """Custom shutdown logic for POS service"""
+        # Shutdown background scheduler
+        try:
+            from app.scheduler import shutdown_scheduler
+            shutdown_scheduler()
+            self.logger.info("Background scheduler stopped successfully")
+        except Exception as e:
+            self.logger.error(f"Failed to stop background scheduler: {e}", exc_info=True)
+
         # Database cleanup is handled by the base class
         pass