Prepare the head-prototype owner sign-off sheet (before/after at 1.85m)

TODO.md

@@ -108,6 +108,10 @@ the rest of §C remains the broad review checklist.
       must be re-measured at rollout.
 - [ ] Get owner sign-off on the one-variant prototype, then roll the approved head/face into the
       other 11 variants one asset family at a time, with a before/after sheet per batch.
+      **Blocked on owner sign-off.** Sign-off material is ready: the s48 prototype vs the current
+      `_face` at 1.85 m front/three-quarter/profile
+      (`docs/blender_previews/sheet_head_proto_before_after.jpg`); the s24/s48/s64 comparison table
+      is in `docs/3d-model-review.md`. Rollout waits for the owner's go/no-go.
 
 ### 4. Hands and grip prototype