curl --request POST \
  --url https://api.wacht.dev/api/agent/contexts/{id}/execute \
  --header 'Content-Type: multipart/form-data' \
  --cookie session_id= \
  --form 'message=Hello, can you help me?' \
  --form 'files=<string>' \
  --form files.items='@example-file'

{
  "message": {
    "id": "msg_abc123",
    "role": "user",
    "content": {
      "type": "text",
      "text": "Hello, how can you help?"
    },
    "timestamp": "2024-01-15T10:30:00Z",
    "metadata": {}
  },
  "status": "complete",
  "tool_calls": [],
  "usage": {
    "prompt_tokens": 123,
    "completion_tokens": 123,
    "total_tokens": 123
  }
}