[
  {"src": "/tmp/council-bin.glb",     "id": "bin",         "category": "street", "height_m": 1.0, "tris": 5000},
  {"src": "/tmp/milk-crate-stack.glb","id": "crate_stack", "category": "fit",    "height_m": 0.9, "tris": 5000}
]