Day 5: Standing pose, slow servos, and fixing the backward tilt

Today's focus: getting the robot to stand up cleanly instead of snapping into pose. 1. Added a pre-stand pose. The robot now moves to a folded pre-stand position first, holds for 2 seconds, then transitions into standing. Gives a known starting point every time. 2. Slowed the servos down. MG996R at full speed is too aggressive it slams into position and the chassis jerks. Replaced direct servo.write(target) calls with a stepper that moves 1° at a time with a 50 ms delay, ~5% of full speed. All four servos in a joint group step in parallel so they arrive together. 3. Fixed the backward tilt. First test, the robot tipped backward while standing front legs were pushing up while the rear was still folded, so the center of mass sat too far back. Fix: the rear pair now starts moving 3 seconds before the front pair within each joint group (top → middle → bottom). Shifts weight forward before the front lifts. Next time: Test if 3 seconds of rear head-start is enough, or if the bottom joints need more (biggest sweep, 75–95°). Also add a reverse "sit down" sequence so it can lower itself instead of just cutting power and dropping.