refactor(app): remove theme param; unify server port env var

- Removed the theme argument from gr.Blocks to prevent an undefined reference
- Changed server port to prefer GRADIO_SERVER_PORT over PORT to align with Gradio defaults

app.py

@@ -462,7 +462,6 @@ class SpacesApp:
             
             with gr.Blocks(
             title="Secure AI Agents Suite",
-            theme=theme,
             css=custom_css,
             analytics_enabled=False
             ) as interface:
@@ -968,7 +967,7 @@ if __name__ == "__main__":
         
         # Configure server settings for Spaces
         server_name = os.getenv("HOST", "0.0.0.0")
-        server_port = int(os.getenv("PORT", "7860"))
+        server_port = int(os.getenv("GRADIO_SERVER_PORT", os.getenv("PORT", "7860")))
         
         logger.info(f"Starting application on {server_name}:{server_port}")