Add concealment meter and skinned collider baker; reorganize assets

- ConcealmentMeter: standalone component measuring the percentage of the
  character volume embedded inside environment geometry (bake -> voxelize via
  column ray-stabbing parity -> classify interior voxels against box/sphere/
  capsule/convex colliders and terrain). Always-on, throttled, gizmo debug.
- SkinnedColliderBaker: sole per-frame collider bake owner for skinned rigs.
  MeshPainter now delegates baking and only borrows BakedMesh for the GPU
  raster and cache refresh, so the collider stays fresh outside paint mode.
- Move pose assets to Assets/Poses, retire unused Insect scripts to
  Assets/Unused, restore Paintman.controller; mode scripts and scene updated.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Assets/Unused/InsectMode.cs

@@ -0,0 +1,38 @@
+/// <summary>
+/// Insect / surface-walk mode: the player crawls along any surface (walls, ceilings,
+/// arbitrary slopes) via <see cref="InsectController"/>. The gravity-based
+/// <see cref="PlayerCharacterController"/> is disabled so the two never fight. The
+/// camera keeps its world-up orbit; painting is off.
+/// </summary>
+public class InsectMode : GameMode
+{
+    public override string DisplayName => "Insect";
+
+    public override void Enter()
+    {
+        if (Manager.Player)
+            Manager.Player.enabled = false; // stop the gravity controller (its Update/gravity)
+
+        //if (Manager.Insect)
+        //{
+        //    Manager.Insect.enabled = true;
+        //    Manager.Insect.ControlEnabled = true;
+        //    Manager.Insect.SnapToSurface();
+        //}
+
+        if (Manager.CameraInput)
+            Manager.CameraInput.LookMode = ThirdPersonOrbitInput.OrbitLookMode.AlwaysActive;
+
+        if (Manager.Painter)
+            Manager.Painter.PaintingEnabled = false;
+    }
+
+    public override void Exit()
+    {
+        //if (Manager.Insect)
+        //    Manager.Insect.enabled = false;
+
+        if (Manager.Player)
+            Manager.Player.enabled = true;
+    }
+}