Update main.py

main.py

@@ -147,12 +147,14 @@ class HVACApp:
                 "embodied_energy": {
                     "total_embodied_carbon_kgco2e": 0,
                     "breakdown_by_component": {},
-                    "charts": {}
+                    "charts": {},
+                    "material_inventory": []
                 },
                 "materials_cost": {
                     "total_cost_usd": 0,
                     "breakdown_by_component": {},
-                    "charts": {}
+                    "charts": {},
+                    "material_inventory": []
                 }
             }
         
@@ -540,5 +542,4 @@ if __name__ == "__main__":
         logger.exception("Application error")
 
 
-sys.path.append(os.path.join(os.path.dirname(__file__), 'data'))
-
+sys.path.append(os.path.join(os.path.dirname(__file__), 'data'))