Get Quickwit metrics snapshot

curl --request GET \
  --url https://example.com/api/admin/metrics \
  --cookie better-auth.session_token=

{
  "build": {
    "buildDate": "<string>",
    "commitHash": "<string>",
    "version": "<string>"
  },
  "fetchedAt": "<string>",
  "resources": {
    "fdsMax": 123,
    "fdsOpen": 123,
    "memoryRssBytes": 123,
    "walDiskBytes": 123
  },
  "saturation": {
    "cpuBusyRatio": 123
  },
  "uptimeSeconds": 123
}