Diff two published versions of an API

Compares two already-published versions of the same API (addressed by apiId + fromTag + toTag) and returns the oasdiff-backed structured changelog plus a breaking-change list. Lighter-weight than the multipart /specs/diff endpoint because the caller doesn't have to upload either spec — the backend reads them from its own version history. Returns 503 if the oasdiff service is disabled in this deployment.

curl -X GET "https://app.spec0.io/api/v1/public/specs/version-diff?apiId=497f6eca-6276-4993-bfeb-53cbbbba6f08&fromTag=string&toTag=string"

{
  "fromTag": "string",
  "toTag": "string",
  "changelog": {},
  "breakingChanges": [
    {}
  ]
}

{
  "error": "string",
  "message": "string"
}

{
  "status": 0,
  "title": "string",
  "detail": "string",
  "type": "string",
  "instance": "string"
}

{
  "status": 0,
  "title": "string",
  "detail": "string",
  "type": "string",
  "instance": "string"
}