Fix API key name back to anthropic_key

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

app.py

@@ -550,9 +550,9 @@ STAGE_FOCUS = {
 
 def get_client():
     """Initialize Anthropic client"""
-    api_key = os.environ.get("anthropoic_key")
+    api_key = os.environ.get("anthropic_key")
     if not api_key:
-        raise ValueError("anthropoic_key environment variable not set. Add it in Space Settings > Repository secrets.")
+        raise ValueError("anthropic_key environment variable not set. Add it in Space Settings > Repository secrets.")
     return anthropic.Anthropic(api_key=api_key)
 
 def call_claude(system_prompt, messages, context=""):