Bounded count aggregates (counts only, never content)

curl --request GET \
  --url https://3ngram-server-production.up.railway.app/api/v1/stats \
  --header 'X-API-Key: <api-key>'

{
  "activeMemories": 4503599627370495,
  "commitmentsByStatus": {},
  "memoriesByType": {},
  "supersededMemories": 4503599627370495
}