feat(body): pose the arms down, add a front-angle shot

The character now stands with its arms at its sides instead of in a bind A-pose,
and there is a second camera to prove it: the third-person shot only ever showed
the pawn's back, so a front-facing pose defect was invisible in review.

  demo-third-person-front  camera on the road, ~6 m in front, looking back north
                           at the pawn; embedded in Screenshots/README.md as shot 7.

The pose work itself is a chain of measured findings, all recorded in TODO.md:

- clip data is exported relative to the REST pose, so arms-down offsets held only in
  the keys arrived as a ±20 degree swing around an A bind;
- a rest-pose bake alone does not move the mesh: the MPFB mesh has shape keys, the
  armature modifier cannot be applied while they exist, and the vertices stayed in
  the A shape (X span unchanged at 1.051 m). Clearing the shape keys, baking the
  deformation into the vertices and re-binding is what made bind and clips agree.

Not settled, and left as an open item rather than a claim: the base pose uses
inverted signs to compensate for the FBX axis mapping, the upper arms clip into the
torso, and the fingers splay. An aim-based pose module was written and then removed
- applied without the vertex bake it produced arms raised in a V, and a half-working
shared module is worse than none. The proper solve is 0.2.2: apply the standing pose
at character creation, then author clips against that bind.

Tools/ue_build_review_map.py

@@ -319,6 +319,10 @@ try:
             # the visible body and its idle clip are what the shot is for.
             # Demo_PlayerStart is at (-13336, -1150, 600), yaw 90 (facing +Y).
             ("demo-third-person", unreal.Vector(-13336, -1750, 780), unreal.Vector(-13336, -1150, 560), 58.0),
+            # Front view of the same pawn: the third-person shot only ever shows its
+            # back, so a pose defect there is invisible. The pawn spawns facing +Y
+            # (yaw 90), so the camera stands on the road side and looks back north.
+            ("demo-third-person-front", unreal.Vector(-13336, -520, 700), unreal.Vector(-13336, -1150, 540), 55.0),
         ]
         seq = spawn(unreal.GigLineShotActor, unreal.Vector(0, 0, 300), "ShotSequencer")
         if seq:

Tools/visual_targets.json

@@ -72,6 +72,18 @@
         "Art/reference/hollywood/el-capitan-facade-day-wikimedia-2009-10-27.jpg"
       ],
       "expect": "Third-person view of the player body standing on the north sidewalk, full figure visible from behind, the hero facade across the street, daylight"
+    },
+    {
+      "name": "demo-third-person-front",
+      "shot": "Screenshots/demo/review-demo-third-person-front.png",
+      "size": [
+        1920,
+        1080
+      ],
+      "references": [
+        "Art/reference/hollywood/el-capitan-facade-day-wikimedia-2009-10-27.jpg"
+      ],
+      "expect": "Front view of the player body from the road: both arms hanging at the sides, hands down by the hips, face and chest visible, hero facade behind the camera"
     }
   ]
 }