Improve filter handling in inventory listing by adding fallback for unknown users, locations, and items

routes.py

@@ -156,16 +156,22 @@ def list_inventory():
     if filter_by and id:
         column = FILTER_MAP.get(filter_by)
         if column is not None:
+            filter_name = None
             if filter_by == 'user':
-                filter_name = db.session.query(User).filter(User.id == id).first().full_name
+                user = db.session.query(User).filter(User.id == id).first()
+                filter_name = user.full_name if user else "Unknown User"
             elif filter_by == 'location':
-                filter_name = db.session.query(Room).filter(Room.id == id).first().full_name
+                room = db.session.query(Room).filter(Room.id == id).first()
+                filter_name = room.full_name if room else "Unknown Location"
             else:
-                filter_name = db.session.query(Item).filter(Item.id == id).first().description
+                item = db.session.query(Item).filter(Item.id == id).first()
+                filter_name = item.description if item else "Unknown Item"
+            
             query = query.filter(column == id)
         else:
             return "Invalid filter_by parameter", 400
 
+
     return render_paginated_table(
         query=query,
         page=page,