refs: survey the sibling project and recalibrate the hero facade

Tools/sibling_asset_audit.py reads the sibling security-game project's prop
library straight from the GLB headers: 20 street props, 11.8k triangles, every
one with a Blender source. The 50 .blend sources are copied to
Art/props/blender_src/ with a manifest; nothing is imported into Unreal yet. Its
building meshes are deliberately not taken - they are Godot GLBs built around a
29.6 m facade that this project measured at 25.75 m.

The facade proportions were wrong against the photograph: 5.7 m of blank wall
above the capitals. Entablature is now 3.4 m, parapet 2.2 m, with architrave and
cornice bands and square pedestals, so the elevation reads as layered stone.

Tools/sibling_asset_audit.py

@@ -0,0 +1,107 @@
+# Audit the sibling Gig Line project for assets this project can reuse.
+#
+#   python3 Tools/sibling_asset_audit.py            # summary
+#   python3 Tools/sibling_asset_audit.py --manifest # write Art/props/reuse-manifest.json
+#
+# The sibling project (…/06-games/security-game) is a Godot 4 security game by
+# the same author that researched this block first. Its street props are small,
+# generic and far cheaper to reuse than to remodel; its building meshes are not
+# reusable because they are Godot GLBs built to a different contract.
+#
+# What this tool does NOT do: copy anything, decide licence, or assume a prop
+# matches this project's proportions. It reports name, size, format and whether
+# a Blender source exists, so the copy list can be chosen deliberately.
+
+import argparse
+import json
+import os
+import struct
+import sys
+
+SIBLING = "/run/media/system/DATA/Documents/06-games/security-game"
+PROPS_GLB = os.path.join(SIBLING, "assets/models/blender/props")
+SRC_BLEND = os.path.join(SIBLING, "assets/models/blender_src")
+OUT = "Art/props/reuse-manifest.json"
+
+
+def glb_stats(path):
+    """Triangle count and bounds from a GLB, without any dependency."""
+    with open(path, "rb") as f:
+        data = f.read()
+    if data[:4] != b"glTF":
+        return None
+    json_len = struct.unpack("<I", data[12:16])[0]
+    doc = json.loads(data[20 : 20 + json_len].decode("utf-8"))
+    tris = 0
+    for mesh in doc.get("meshes", []):
+        for prim in mesh.get("primitives", []):
+            idx = prim.get("indices")
+            if idx is not None:
+                tris += doc["accessors"][idx]["count"] // 3
+    # bounds across all positions
+    mins = [1e9] * 3
+    maxs = [-1e9] * 3
+    for mesh in doc.get("meshes", []):
+        for prim in mesh.get("primitives", []):
+            acc = prim.get("attributes", {}).get("POSITION")
+            if acc is None:
+                continue
+            a = doc["accessors"][acc]
+            if "min" in a and "max" in a:
+                mins = [min(m, v) for m, v in zip(mins, a["min"])]
+                maxs = [max(m, v) for m, v in zip(maxs, a["max"])]
+    size = [round(maxs[i] - mins[i], 3) for i in range(3)] if mins[0] < 1e8 else None
+    return {"triangles": tris, "size_gltf": size, "materials": len(doc.get("materials", []))}
+
+
+def main():
+    ap = argparse.ArgumentParser()
+    ap.add_argument("--manifest", action="store_true")
+    args = ap.parse_args()
+    if not os.path.isdir(PROPS_GLB):
+        sys.exit(f"missing {PROPS_GLB}")
+
+    rows = []
+    for name in sorted(os.listdir(PROPS_GLB)):
+        if not name.endswith(".glb"):
+            continue
+        stem = name[:-4]
+        path = os.path.join(PROPS_GLB, name)
+        stats = glb_stats(path) or {}
+        source = os.path.join(SRC_BLEND, stem + ".blend")
+        rows.append({
+            "prop": stem,
+            "glb": name,
+            "bytes": os.path.getsize(path),
+            "blend_source": os.path.basename(source) if os.path.exists(source) else None,
+            "blend_bytes": os.path.getsize(source) if os.path.exists(source) else None,
+            **stats,
+        })
+
+    for r in rows:
+        src = "blend" if r["blend_source"] else "glb-only"
+        size = r.get("size_gltf")
+        dims = "x".join(f"{v:.2f}" for v in size) if size else "?"
+        print(f"{r['prop']:18} {r['triangles']:5} tris  {dims:>18} glTF m  "
+              f"mats {r.get('materials', 0)}  {src}")
+
+    print(f"\n{len(rows)} props, {sum(r['bytes'] for r in rows)//1024} KB of GLB, "
+          f"{sum(r['triangles'] for r in rows)} triangles total")
+    print("glTF is Y-up and Blender is Z-up: the exporter swaps Y/Z, so `size_gltf` "
+          "lists X, height, depth — not X, Y, Z as authored.")
+
+    if args.manifest:
+        os.makedirs(os.path.dirname(OUT), exist_ok=True)
+        with open(OUT, "w") as f:
+            json.dump({
+                "source_project": SIBLING,
+                "scanned": "assets/models/blender/props + assets/models/blender_src",
+                "licence": "project-owned (same author); confirm before shipping",
+                "note": "audit only — nothing has been copied",
+                "props": rows,
+            }, f, indent=2)
+        print(f"wrote {OUT}")
+
+
+if __name__ == "__main__":
+    main()