curl -X PATCH 'https://app.memorylake.ai/openapi/memorylake/api/v3/actors/act-a1b2c3d4e5f6' \
  -H 'Authorization: Bearer sk_xxxxxx' \
  -H 'Content-Type: application/json' \
  -d '{
    "display_name": "Alice Chen (VIP)",
    "metadata": {
      "tier": "enterprise",
      "region": "us-west",
      "account_manager": "bob@example.com"
    }
  }'

{
  "success": true,
  "data": {
    "id": "act-a1b2c3d4e5f6",
    "custom_id": "user-ext-001",
    "actor_type": "HUMAN",
    "display_name": "Alice Chen (VIP)",
    "description": "Primary end user for the mobile app",
    "metadata": {
      "tier": "enterprise",
      "region": "us-west",
      "account_manager": "bob@example.com"
    },
    "created_at": "2025-03-10T08:00:00Z",
    "updated_at": "2025-06-15T11:20:00Z"
  }
}