List channels (agents) accessible by this API key

Example response

[
  {
    "id": "clxyz456",
    "name": "My Agent",
    "description": "A helpful assistant",
    "avatarUrl": "https://example.com/avatar.png",
    "webhookUrl": "https://example.com/webhook",
    "lastActiveAt": "2025-01-01T12:00:00.000Z",
    "createdAt": "2025-01-01T00:00:00.000Z"
  }
]