remove cors_allowed_origins from response

Co-authored-by: Copilot <[email protected]>

Author: ChingEnLin

backend/main.py

@@ -45,11 +45,10 @@
 
 @app.get("/health")
 async def health_check():
-    """Health check endpoint that also shows CORS configuration."""
+    """Health check endpoint."""
     return {
         "status": "healthy",
         "cors_production_mode": is_production,
-        "cors_allowed_origins": allowed_origins,
     }