Variable WALK_ANIMATIONConst

Walking cycle animation (앞으로 걷기 - 보행 사이클)

Natural walking gait with alternating leg movement. Includes hip swing, knee bend during swing phase, foot placement, and pelvis tilt.

Animation phases:

1. Left foot forward (0.0s): Left leg extends, right leg pushes off
2. Left mid-stance (0.2s): Left foot plants, right leg swings forward
3. Right foot forward (0.4s): Right leg extends, left leg pushes off
4. Right mid-stance (0.6s): Right foot plants, left leg swings forward

Duration: 800ms (complete left-right step cycle)