Add per-pose camera target Y offset and route ceiling offset to camera

Add cameraTargetYOffset to PlayerPose so each pose can offset the
Cinemachine ThirdPersonCamera follow/look target independently of the
body mesh. PlayerCharacterController gains a cameraTarget reference
(auto-resolved via the "CameraTarget" child, base position captured in
Awake) and a single-writer SetCameraTargetLocalYOffset. PlayerPoseController
eases the per-pose camera offset and composes it with the shared ceiling
offset, so the camera target follows the ceiling lift in lockstep with the
mesh. Wire cameraTarget explicitly in SampleScene.

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

Assets/Scenes/SampleScene.unity

@@ -4634,6 +4634,7 @@ MonoBehaviour:
   wallTopOutBoost: 0.3
   cameraOrbit: {fileID: 0}
   meshOffsetTarget: {fileID: 0}
+  cameraTarget: {fileID: 1774267802}
 --- !u!114 &1141039643
 MonoBehaviour:
   m_ObjectHideFlags: 0