feat(hero): stepped medallion relief, seated on the parapet face

The medallions were not just flat - they were buried. seat_on_front put
Hero_Medallion at offset 0.08 (front Y -0.42) while the 1.2 m-deep parapet stands
at Y -0.15, so both discs sat inside the parapet and never rendered. The motto
band and surround have the same burial (offset 0.06) and are a separate follow-up.

- Three stepped layers per medallion with per-layer prefixes so seat_on_front gives
  each its own stand-off: Rim (0.55 m, dark, offset 0.36 -> Y -0.14), Field
  (0.38 m, light, offset 0.43 -> Y -0.07), Boss (0.15 m, dark, offset 0.50 -> Y 0.00).
  A single Hero_Medallion prefix would both flatten the relief and (via startswith)
  swallow the specific prefixes, so it is removed.
- Moved from +/-6.2 (inside the inscription text, which spans +/-6.87) to +/-9.8.
- Fixed Tools/review/hero_iterate.sh, which still had the pre-tools-move
  'cd dirname/..' and landed in Tools/ instead of the repo root.

Rendered and judged; the advisory two-model judge (no, 0.93) no longer flags the
medallions. Owner review pending.

Tools/review/hero_iterate.sh

@@ -10,7 +10,7 @@
 # order is load-bearing. The Blender save happens BEFORE the FBX export, so a read-only .blend makes
 # the build look successful while the old FBX is reused silently - hence the chmod at the top.
 set -uo pipefail
-cd "$(dirname "$0")/.." || exit 1
+cd "$(dirname "$0")/../.." || exit 1
 
 ENGINE="${ENGINE:-/run/media/system/DATA/Engines/UE_5.8.4}"
 BLENDER_FILES="${BLENDER_FILES:-/var/lib/flatpak/app/org.blender.Blender/x86_64/stable/active/files}"