Give the figure real girdles, fix orbit pinning, add roller pads

Shoulder and pelvis widths grow to human-like proportions per profile
(shoulders wider than hips for neutral/male, reversed for female) and
are now drawn — bars across the attach points that read near-full-width
face-on and as a shoulder/hip nub in profile, so limbs visibly hang
from a torso instead of a point. Orbiting no longer re-solves IK pins
in the rotated view (pins are canvas targets in the authored camera):
the pose resolves first and the posed body rotates, which fixes hands
sticking to stale screen points mid-orbit (Cat-Cow, Bird Dog, Plank).
Leg Extension and Leg Curl swap their ankle bars for a machine roller
disc — a new `roller` prop riding the shin's press side. Fixtures
regenerated; both renderers updated in lockstep.

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

Exercise Library/Leg Extension/visual.svg

@@ -9,10 +9,12 @@
   <circle cx="114.0" cy="90.0" r="3.5" fill="#6b7180"/>
   <path id="arm_l" d="M 97.7 37.2 L 105.5 66.2 L 120.5 92.2" stroke="#a9afba" stroke-width="5" stroke-linecap="round" stroke-linejoin="round"/>
   <path id="leg_l" d="M 124.0 118.0 L 169.3 110.0 L 209.2 107.2 L 208.4 96.2" stroke="#86cfc5" stroke-width="5" stroke-linecap="round" stroke-linejoin="round"/>
+  <path id="girdle" d="M 97.7 37.2 L 91.7 35.2 L 91.7 35.2" stroke="#3a3f4b" stroke-width="5" stroke-linecap="round" stroke-linejoin="round"/>
+  <path id="pelvisBar" d="M 124.0 118.0 L 118.0 116.0 L 118.0 116.0" stroke="#3a3f4b" stroke-width="5" stroke-linecap="round" stroke-linejoin="round"/>
   <path id="spine" d="M 118.0 116.0 Q 101.7 75.6 91.7 35.2" stroke="#3a3f4b" stroke-width="6" stroke-linecap="round" stroke-linejoin="round"/>
-  <path id="arm_r" d="M 91.7 35.2 L 99.5 64.2 L 114.5 90.2" stroke="#3a3f4b" stroke-width="6" stroke-linecap="round" stroke-linejoin="round"/>
   <path id="leg_r" d="M 118.0 116.0 L 163.3 108.0 L 203.2 105.2 L 202.4 94.2" stroke="#0d9488" stroke-width="6" stroke-linecap="round" stroke-linejoin="round"/>
-  <path d="M 205.6 97.2 L 206.8 115.2" stroke="#6b7180" stroke-width="7" stroke-linecap="round" stroke-linejoin="round"/>
+  <path id="arm_r" d="M 91.7 35.2 L 99.5 64.2 L 114.5 90.2" stroke="#3a3f4b" stroke-width="6" stroke-linecap="round" stroke-linejoin="round"/>
+  <circle cx="207.6" cy="98.1" r="5" fill="#6b7180"/>
   <circle id="head" cx="97.2" cy="16.0" r="10" fill="white" stroke="#3a3f4b" stroke-width="6"/>
   <line id="nose" x1="106.6" y1="19.4" x2="113.2" y2="21.8" stroke="#3a3f4b" stroke-width="4" stroke-linecap="round"/>
   <g font-family="-apple-system, Helvetica, sans-serif" font-size="11" fill="#6b7180">