Start a new agent execution

curl --request POST \
  --url https://app.kapso.ai/api/v1/agents/{agent_id}/executions \
  --header 'Content-Type: application/json' \
  --header 'X-API-Key: <api-key>' \
  --data '{
  "message": "I need help with my order",
  "phone_number": "+1234567890"
}'

{
  "data": {
    "id": "execution-789ghi",
    "agent_id": "agent-123abc",
    "thread_id": "thread-101jkl",
    "status": "running",
    "started_at": "2023-11-07T05:31:56Z",
    "ended_at": "2023-11-07T05:31:56Z",
    "duration": 123
  }
}