Improve environment variable handling for API keys

app.py

@@ -1,7 +1,18 @@
 import os
 import gradio as gr
+from dotenv import load_dotenv
 from src.app import DryingApp
 
+# Load environment variables
+load_dotenv()
+
+# Check if API keys are available
+if not os.getenv("OPENROUTER_API_KEY"):
+    print("Warning: OPENROUTER_API_KEY environment variable not set")
+    
+if not os.getenv("STABILITY_API_KEY"):
+    print("Warning: STABILITY_API_KEY environment variable not set")
+
 # Initialize the Drying Assistant application
 app = DryingApp()