Draft ADR-0018 (Stage 2 runtime rig) and mark the remaining contract-bake items blocked

TODO.md

@@ -82,10 +82,15 @@ baseline sheet.
       ADR) indicated; do not rebuild on the warped base.**
 - [ ] Skin the Quaternius mesh and verify Idle, Walk, seated and arm-down poses. The old
       MPFB/arm-retarget warps are not a reference; judge the Quaternius result directly.
+      **Blocked** on the ADR-0018 decision (option 1 vs 2 rest positions / rig); the arm-down
+      rest pose is already baked and verified, but Idle/Walk/seated verification needs the
+      chosen rest positions first.
 - [ ] Retarget Idle and Walk from the 24 Quaternius clips to the contract rig; discard
       combat, gun and sword clips. Verify looping, foot contact and frame rate in Godot.
+      **Blocked** on ADR-0018 (retarget target changes with option 1 vs 2).
 - [ ] Map the five slots, unwrap per slot, bake 256² AO/albedo/normal/ORM maps and check
       texel density before any roster build.
+      **Blocked** on ADR-0018 (the mesh is not finalised until the rest positions/rig are chosen).
 
 ### 3. Silhouette gate