curl --request GET \
  --url https://api.staging.kathan.tech/credits/balance \
  --header 'Authorization: Bearer <token>' \
  --header 'X-User-ID: <api-key>'

{
  "balance_credits": 123,
  "reserved_credits": 123,
  "spendable_credits": 123,
  "lifetime_purchased_credits": 123,
  "credit_floor": -10
}