Credits API

curl -H "X-API-Key: sk-your-key-here" \
     https://your-api-domain.com/image-forge-api/v1/credits/balance

{
  "balance": 150,
  "planName": "Pro",
  "userId": "user_abc123"
}

curl -X POST \
     -H "X-API-Key: sk-your-key-here" \
     -H "Content-Type: application/json" \
     -d '{
       "action": "export",
       "imageCount": 5,
       "deduct": true
     }' \
     https://your-api-domain.com/image-forge-api/v1/credits/check

{
  "sufficient": true,
  "balance": 145,
  "cost": 5,
  "remaining": 140
}

{
  "error": "Insufficient credits. You have 3 but need 5. Upgrade your plan or buy a credit pack."
}