Add NEXT_PUBLIC_SUPABASE_URL, SUPABASE_SERVICE_ROLE_KEY, ULTRAVOX_API_KEY, and OPENAI_API_KEY to .env.local.

{
  "message": "TypeError: fetch failed",
  "details": "TypeError: fetch failed\n\nCaused by: Error: getaddrinfo ENOTFOUND guphamjjbplbtohdbcmt.supabase.co (ENOTFOUND)\nError: getaddrinfo ENOTFOUND guphamjjbplbtohdbcmt.supabase.co\n    at GetAddrInfoReqWrap.onlookupall [as oncomplete] (node:dns:122:26)",
  "hint": "",
  "code": ""
}