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/Chest Press/info.md

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+# Chest Press
+
+The seated horizontal press — the machine bench press, pushing the handles
+forward from the chest.
+
+- **Category:** Main circuit
+- **Type:** Machine-based horizontal press
+- **Targets:** Pectorals, anterior deltoids, triceps
+
+## Setup
+
+Adjust the seat so the handles sit at mid-chest height. Grip the handles, set
+your back against the pad, and keep your wrists straight and stacked over the
+forearms.
+
+## Execution
+
+1. Push the handles forward until your arms are nearly extended — stop short of
+   locking the elbows.
+2. Pause briefly, then return slowly until the handles are back at your chest.
+3. Keep your shoulder blades gently pinned to the pad throughout.
+
+## Cues
+
+- Drive through the palms; wrists stay straight, not bent back.
+- Don't let the elbows drop far below the handles at the bottom.
+- Return under control — resist the weight rather than letting it pull you back.
+
+## Common Mistakes
+
+- Letting the elbows sink too low, straining the shoulders.
+- Bouncing the handles at the chest to start the next rep.
+- Locking the elbows hard at full extension.
+
+## Progression
+
+Add weight in small plates once all four sets of ten are controlled; alternate
+to a single-arm press to expose and correct side-to-side differences.