Ship the 47-exercise library in-app: export, fixtures, tests, docs

render.py --export bundles the 25 new motion rigs and info pages;
figure-fixtures.json regenerated for all 47 (the Swift solver reproduces
every new motion, including negative-y pins and the new prop uses). The
fixture count assertion moves to 47, and the no-bundled-motion test now
uses Treadmill - a permanent COVERAGE.md exclusion - since Bench Press
exists. 48 tests green; watch target builds. Coverage handoff complete -
TODO-coverage.md retired.

Claude-Session: https://claude.ai/code/session_01HJDQQDA9QdP8zByg43H5v3

Workouts/Resources/ExerciseMotions/Barbell Squat.info.md

@@ -0,0 +1,39 @@
+# Barbell Squat
+
+The barbell back squat — bar across the upper back, sit down between the
+heels, stand back up.
+
+- **Category:** Main circuit
+- **Type:** Free-weight compound squat
+- **Targets:** Quadriceps, glutes, adductors, trunk
+- **Prescription:** 4 × 6–8
+
+## Setup
+
+Set the bar on your upper traps (not the neck), hands just outside the
+shoulders, and step back from the rack. Feet shoulder-width, toes slightly
+out, brace before every rep.
+
+## Execution
+
+1. Sit down and back — hips and knees bend together, chest stays up.
+2. Descend until the thighs reach at least parallel, knees tracking over
+   the toes.
+3. Drive the floor apart and stand back up to full lockout.
+
+## Cues
+
+- Big breath and brace at the top; exhale at the finish.
+- The bar stays over mid-foot — watch the sideways bar path, not the mirror.
+- Elbows down under the bar, not flared behind it.
+
+## Common Mistakes
+
+- Knees caving inward out of the bottom.
+- Heels lifting — weight drifting onto the toes.
+- Chest collapsing forward into a good-morning.
+
+## Progression
+
+Master the Bodyweight Squat and Goblet Squat first; add weight in small
+jumps only while depth and knee tracking hold.