Add the remaining census stations: Pec Deck, Rear Delt Fly, cable staples

Pec Deck and Rear Delt Fly author the face-on and from-behind cameras;
Triceps Pushdown and Face Pull are the cable station's two entries per
the coverage model (cable curl/crossover are considered exclusions).

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

Exercise Library/Rear Delt Fly/info.md

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+# Rear Delt Fly
+
+The reverse pec deck — facing the pad, arms sweep from the front out
+wide and back, hitting what pressing never touches.
+
+- **Category:** Main circuit
+- **Type:** Machine-based reverse fly
+- **Targets:** Rear delts, mid-back
+- **Prescription:** 3 × 12–15, light
+
+## Setup
+
+Set the handles to the rear-fly position and sit facing the pad, chest
+supported, handles together in front at shoulder height, arms long with
+soft elbows.
+
+## Execution
+
+1. Sweep both arms out and back as far as the shoulder blades allow.
+2. Pause with the arms wide, squeezing between the shoulder blades.
+3. Return forward under control without the stack touching down.
+
+## Cues
+
+- Lead with the knuckles, arms long — it's a sweep, not a row.
+- Chest glued to the pad; no leaning back for leverage.
+- Light weight, full arc — momentum defeats the rear delts instantly.
+
+## Common Mistakes
+
+- Bending the elbows into a rowing motion.
+- Loading too heavy and shortening the arc.
+- Shrugging the traps into the sweep.
+
+## Progression
+
+More reps and a longer pause out wide before more weight; the Face Pull
+covers the same territory from the cable stack.