Added open ai api key

Chatbot.py

@@ -36,8 +36,10 @@ def main():
         """)
         
     # Set OpenAI API key
-    # if openai_api_key:
-    #     os.environ["OPENAI_API_KEY"] = openai_api_key
+    openai_api_key = os.getenv("OPENAI_API_KEY")
+    if not openai_api_key:
+        st.error("OpenAI API key not found! Please check your .env file.")
+        st.stop()
 
     # Main chat interface
     st.title("🤖 Intelligent Customer Support Agent")