Author the machine exercise circuit with props and corrected hip machine motions

Fourteen Planet Fitness machine exercises join the rig library, each with
authored motion, info page, and schematic equipment via the new props layer
(scene shapes, cables, bars, pads) rendered in lockstep by render.py and the
in-app figure renderer. Abductor and Adductor are authored face-on with the
real seated machine motion — knees-bent legs swinging apart/together against
knee pads — replacing the earlier middle-split depiction. The watch target
now bundles the figure renderer and motion rigs too.

Claude-Session: https://claude.ai/code/session_01LEoff8bXGBS83tK1c55Mf7

Exercise Library/Rotary/info.md

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+# Rotary
+
+The rotary torso machine — controlled trunk rotation that isolates the
+obliques.
+
+- **Category:** Main circuit
+- **Type:** Machine-based trunk rotation
+- **Targets:** Obliques, deep core
+- **Prescription:** 4 × 10
+
+## Setup
+
+Sit tall with your hips squared and locked against the pads. Rest your
+forearms on the pads and grip the handle in front of your chest so the trunk,
+not the arms, drives the machine.
+
+## Execution
+
+1. Rotate your torso to one side in a smooth, controlled arc, keeping your hips
+   still.
+2. Pause at the end of the range without letting the weight pull you further.
+3. Return through center and rotate to the other side with the same control.
+
+## Cues
+
+- Twist from the waist — the obliques generate the movement, not the arms.
+- Keep the hips and pelvis pinned; only the trunk turns.
+- Move slowly; momentum steals the work from the obliques.
+
+## Common Mistakes
+
+- Throwing the weight with momentum instead of controlling the twist.
+- Pushing with the arms rather than rotating the trunk.
+- Letting the hips swing along with the torso.
+
+## Progression
+
+Add weight once both sides move with equal control; pause two seconds at full
+rotation to kill any momentum.