Upstream unreachable


`type`	`https://docs.frem.sh/reference/api/errors/upstream-unreachable`
HTTP status	`502` Bad Gateway

What it means

An upstream dependency returned an error.

Example detail messages returned with this error:

An upstream call failed. Retry with backoff; persistent failures are worth reporting to support@frem.sh.

All fremforge API errors are RFC 9457 problem+json:

{
  "type": "https://docs.frem.sh/reference/api/errors/upstream-unreachable",
  "title": "Bad Gateway",
  "status": 502,
  "detail": "..."
}

Branch on type, not on title or detail - those are human-readable and may be reworded.