[
  {
    "semantic_unit_id": "domain_icon_01",
    "slide": 1,
    "target_bbox_px": [140, 240, 120, 120],
    "z_index": 20,
    "placement_rule": "uniform contain scaling; no one-axis stretch"
  },
  {
    "semantic_unit_id": "workflow_arrow_01",
    "slide": 1,
    "target_bbox_px": [420, 300, 180, 48],
    "z_index": 15,
    "placement_rule": "uniform contain scaling; no one-axis stretch"
  }
]
