Add reviewed MakeHuman head prototype (vision gate rejected)

docs/blender_previews/README.md

@@ -9,6 +9,7 @@ capture harnesses.
 | --- | --- |
 | [![sheet_npc.jpg](sheet_npc.jpg)](sheet_npc.jpg) <br> `sheet_npc.jpg` | Eight skinned character variants (casual, jacket, coat, hi-vis vest, dress, hoodie, firefighter, guard) with their gear attach points. |
 | [![sheet_npc_baseline.jpg](sheet_npc_baseline.jpg)](sheet_npc_baseline.jpg) <br> `sheet_npc_baseline.jpg` | Neutral studio baseline: 8 characters x front, three-quarter, profile, back, full body and crowd views. |
+| [![sheet_makehuman_head.jpg](sheet_makehuman_head.jpg)](sheet_makehuman_head.jpg) <br> `sheet_makehuman_head.jpg` | Local MakeHuman head prototype: front, three-quarter and profile review views. The vision gate rejected this build (inconsistent globe depth and no visible lid overlap); see [`../makehuman-head-review.md`](../makehuman-head-review.md). |
 | [![sheet_npc_baseline_compare-body.jpg](sheet_npc_baseline_compare-body.jpg)](sheet_npc_baseline_compare-body.jpg) <br> `sheet_npc_baseline_compare-body.jpg` | Neck/shoulder transition: fuller neck base and a lower shoulder root. |
 | [![sheet_npc_baseline_compare-face-detail.jpg](sheet_npc_baseline_compare-face-detail.jpg)](sheet_npc_baseline_compare-face-detail.jpg) <br> `sheet_npc_baseline_compare-face-detail.jpg` | Face detail: nose ala wings, a single rounded mouth and a darker ear concha. |
 | [![sheet_npc_baseline_compare-face.jpg](sheet_npc_baseline_compare-face.jpg)](sheet_npc_baseline_compare-face.jpg) <br> `sheet_npc_baseline_compare-face.jpg` | Face-depth pass: recessed sclera, upper lid and sculpted chin/cheek planes. |