Taper the arm-scale falloff; record the remaining deltoid retopology gap

docs/npc-model-sourcing.md

@@ -218,6 +218,12 @@ it distorts the deltoid/shoulder, the decimated hands are blocky, and the slot
 boundaries are rough — refinement work (arm-scale falloff, project head/hands,
 weight tuning) is the next step.
 
+The arm-scale falloff (1.0 at the shoulder tapering to 1.63 at the fingertip) was
+added and the arms now hang cleanly, but the shoulder junction still shows spiky
+geometry and dark gaps between the arm and torso — a proper retopology of the
+deltoid region (merge/redirect the warped triangles) is the remaining manual
+step, and it is not reliably automatable headlessly.
+
 - MPFB/MakeHuman is installed and run by a contributor, never by CI or the game
   build.
 - Generated bodies and intermediate exports stay in `tmp/` (gitignored); the