curl -X POST "https://app.talkover.ai/api/v1/agents/agent-uuid/flow/validate" \
  -H "Authorization: Bearer talq_your_environment_token_here" \
  -H "Content-Type: application/json" \
  -d '{
    "flow_config": {
      "initial_node_id": "node-greet",
      "nodes": [
        { "id": "node-greet", "type": "say", "content": "Hi!", "next": "node-end" },
        { "id": "node-end", "type": "end" }
      ]
    }
  }'

{
  "success": true,
  "message": "Flow is valid"
}

{
  "success": false,
  "errors": [
    "Duplicate node id: 'node-greet'",
    "Node 'node-end' is unreachable"
  ]
}