:goal_net: fail to start if API key is missing.

app.py

@@ -5,6 +5,10 @@ import json
 import html
 
 api_key = os.environ.get('FEATHERLESS_API_KEY')
+
+if not api_key:
+    raise RuntimeError("Cannot start without required API key. Please register for one at https://featherless.ai")
+
 client = OpenAI(
     base_url="https://api.featherless.ai/v1",
     api_key=api_key