Add a gear-vs-body fit report to the Blender asset tool

`blender_assets.py fit` measures each character head width (skin vertices
weighted to Head in y 1.55-1.81) and clothing radius (cloth skirt in y 0.30-0.52,
pants hip fallback), then prints every attached head/back/chest gear bounding box
with head-band status and x/radial skirt clearance. The report confirms the
glasses width and shoulder-bag coat clip, giving the next fit fixes numbers.
Python tooling 87/87; asset audit clean.

docs/blender-assets.md

@@ -41,6 +41,7 @@ flatpak run org.blender.Blender --background \
   --python "$PWD/tools/blender_assets.py" -- render
 python3 tools/blender_assets.py sheet   # -> docs/blender_previews/sheet_<category>.jpg
 python3 tools/blender_assets.py audit   # stdlib only; exit 1 on any issue
+python3 tools/blender_assets.py fit     # head/clothing fit, per character
 python3 tools/blender_assets.py list
 godot --headless --path . --import      # after any rebuild
 ```