List SSH keys

{
    "success": true,
    "message": "Retrieved 3 SSH keys successfully",
    "code": "SSH_KEYS_RETRIEVED",
    "request_id": "a1b2c3d4",
    "keys": [
        {
            "id": "x7y8z9a0",
            "name": "ml-training-key",
            "public_key": "ssh-rsa AAAAB3NzaC1yc2EAAAADAQAB...",
            "created_at": "2024-12-01T10:30:00Z"
        },
        {
            "id": "b1c2d3e4",
            "name": "web-deploy",
            "public_key": "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5...",
            "created_at": "2024-12-05T14:20:00Z"
        },
        {
            "id": "f5g6h7i8",
            "name": "ci-runner",
            "public_key": "ssh-rsa AAAAB3NzaC1yc2EAAAADAQAB...",
            "created_at": "2024-12-10T09:15:00Z"
        }
    ],
    "metadata": {
        "total_keys": 3
    }
}