Add the Quaternius face/silhouette gate sheet and record the geometry measurements

TODO.md

@@ -816,14 +816,17 @@ blocked rig can no longer block the whole release.
 
 ### Silhouette and face gate (owner)
 
-- [ ] Re-run the silhouette gate at gameplay distance and in portrait against the current
-      `npc_casual`, front / three-quarter / profile. This is a new gate: ADR-0018 removed the
-      proportion warp, so source proportions are now accepted by definition.
-- [ ] Face-fidelity comparison. The Quaternius head is low-poly (≈6.2k tris for the whole body);
-      the 0.9.7 library has a sculpted realistic face. Capture both heads and let the owner pick:
-      (a) full swap, (b) Quaternius for crowd roles with the procedural library for named roles,
-      or (c) add head subdivision/hair cards to the Quaternius head.
-- [ ] Apply the chosen face path within 24,000 tris / 24,000 glTF vertices and re-run the gate.
+- [x] Re-run the silhouette gate at gameplay distance and in portrait against the current
+      `npc_casual`, front / three-quarter / profile. ADR-0018 removed the proportion warp, so
+      source proportions are accepted by definition (head 13.4 % of height, measured by
+      `npc_proportions`).
+- [x] Face-fidelity comparison sheet: [`docs/screens/npc-face-gate/`](../../docs/screens/npc-face-gate/README.md)
+      captures the Quaternius base, the procedural + MakeHuman head and a procedural crowd variant
+      at front / three-quarter / profile / 8 m. The page records the three options (full swap,
+      crowd only, add head detail) and recommends the full swap.
+- [ ] **Owner decision:** pick (a) full swap, (b) crowd only or (c) add head detail from
+      `docs/screens/npc-face-gate/README.md`, then apply it within 24,000 tris / 24,000 glTF
+      vertices and re-run the gate.
 - [ ] Record the decision and its consequence in `MEMORY.md`, `docs/npc-model-sourcing.md` and
       (if it changes the contract) a new ADR. Do not silently lower character fidelity.