{
  "email": "user@example.com",
  "password": "password"
}

{
  "success": true,
  "data": {
    "token": "eyJhbG...",
    "actor": {
      "id": "actor_123",
      "role": "ADMIN",
      "centerId": "center_456"
    }
  }
}

Authorization: Bearer <token>

{
  "success": true,
  "data": {
    "actor": {
      "id": "actor_123",
      "name": "홍길동",
      "email": "user@example.com",
      "role": "ADMIN"
    },
    "center": {
      "id": "center_456",
      "name": "서초센터"
    },
    "authorizedDomains": ["cronozen.com"],
    "memberships": [...]
  }
}

{
  "centerId": "center_789"
}

{
  "success": true,
  "data": {
    "token": "eyJhbG...(new token)",
    "centerId": "center_789"
  }
}