refactor(kit): SM_ asset naming and topology validation per the modeling checklist

- Kit pieces export as SM_Kit_* (Unreal static-mesh convention) while the Blender
  objects keep their readable names; the kit loader strips the prefix so layout
  still addresses pieces by short name.
- facade_kit_build.py validates each piece before handoff (non-manifold edges,
  loose vertices, triangle count) and records the result in the part report:
  16 pieces, all manifold, no loose geometry, 12 tris each.
- ue_import_facade_kit.py removes kit assets the current build no longer produces,
  so a rename cannot leave two generations of the same piece behind.
- Kit re-imported and re-applied (625 pieces); packaged QA still PASS.

Tools/ue_apply_facade_kit.py

@@ -53,7 +53,10 @@ def load_kit() -> dict:
     for data in registry.get_assets(filt):
         mesh = unreal.EditorAssetLibrary.load_asset(str(data.package_name))
         if mesh:
-            kit[mesh.get_name()] = mesh
+            # Assets are SM_-prefixed (Unreal convention); the layout code refers to
+            # pieces by their short name, so key on the name without the prefix.
+            name = mesh.get_name()
+            kit[name[3:] if name.startswith("SM_") else name] = mesh
     return kit