List GPU instance types

curl --request GET \
  --url https://api.case.dev/compute/v1/instance-types \
  --header 'Authorization: Bearer <token>'

{
  "instanceTypes": [
    {
      "name": "gpu_1x_a10",
      "description": "1x NVIDIA A10 GPU",
      "gpu": "1x A10 (24 GB)",
      "pricePerHour": "$0.60",
      "specs": {
        "vcpus": 30,
        "memoryGib": 200,
        "storageGib": 1400
      },
      "regionsAvailable": [
        "us-west-1",
        "us-east-1"
      ]
    }
  ],
  "count": 12
}