curl -X POST "https://api.chatgrid.ai/v1/boards/a1b2c3d4-e5f6-7890-abcd-ef1234567890/edges" \
  -H "Authorization: Bearer cgk_live_a1b2c3d4e5f6g7h8i9j0k1l2m3n4o5p6" \
  -H "Content-Type: application/json" \
  -d '{
    "source_node_id": "e5f6a7b8-c9d0-1234-efab-345678901234",
    "target_node_id": "11223344-5566-7788-99aa-bbccddeeff00",
    "type": "data-flow",
    "data": { "weight": 1.0 }
  }'

{
  "object": "edge",
  "data": {
    "id": "f6a7b8c9-d0e1-2345-fabc-456789012345",
    "board_id": "a1b2c3d4-e5f6-7890-abcd-ef1234567890",
    "source_node_id": "e5f6a7b8-c9d0-1234-efab-345678901234",
    "target_node_id": "11223344-5566-7788-99aa-bbccddeeff00",
    "edge_type": "data-flow",
    "edge_data": { "weight": 1.0 },
    "created_at": "2026-03-15T10:35:00.000Z",
    "updated_at": "2026-03-15T10:35:00.000Z"
  }
}

{
  "object": "error",
  "status": 404,
  "code": "not_found",
  "message": "Source node not found on this board"
}