Disable foot IK on pose playables and add ball pose

- PlayerPoseController: add applyFootIK toggle (default off) and apply it
  to each pose playable so straight-knee idles render straight; Mecanim
  foot IK was bending the knees to plant the feet (162° instead of 180°).
- Add Pose_Ball / Paintman-Ball animation and reorder the pose list.
- Move StraightenKneesTool editor utility under Assets/Unused/Editor.

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

Assets/Models/Paintman-Ball.anim.meta

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