Get platform OAuth provider configuration

Returns which OAuth providers are enabled and their public client IDs. No authentication required — used by login/signup pages at runtime.

curl -X GET "https://loading/api/v1/auth/providers"

{
  "google": {
    "client_id": "string",
    "enabled": true
  },
  "microsoft": {
    "client_id": "string",
    "enabled": true
  }
}