Add Warm-Up and Stretching activity types

Adds WorkoutActivityType.warmUp (HealthKit .preparationAndRecovery) and
.stretching (.flexibility), and retags the six starter splits that were all
mislabeled as Functional Strength:

- Warm-Up:    Upper Body Warm-Up, Lower Body Warm-Up, Morning Wake-Up
- Stretching: Morning Mobility, Full Body Stretch, Evening Stretch

The split editor's activity picker surfaces them automatically (CaseIterable).
Older app versions decode the new raw values as the default type — additive and
not schema-gated, so no quarantine.

Exercise Library/Rear Delt Fly/frames/frame-1.svg

@@ -1,13 +1,33 @@
 <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 180" fill="none">
   <title>Rear Delt Fly</title>
+  <defs>
+    <linearGradient id="grad-leg_l-0" gradientUnits="userSpaceOnUse" x1="153.0" y1="116.0" x2="153.0" y2="117.6"><stop offset="0" stop-color="#3a3f4b"/><stop offset="1" stop-color="#a9afba"/></linearGradient>
+    <linearGradient id="grad-leg_r-0" gradientUnits="userSpaceOnUse" x1="167.0" y1="116.0" x2="167.0" y2="117.6"><stop offset="0" stop-color="#3a3f4b"/><stop offset="1" stop-color="#a9afba"/></linearGradient>
+    <linearGradient id="grad-arm_l-0" gradientUnits="userSpaceOnUse" x1="149.0" y1="32.3" x2="145.9" y2="29.7"><stop offset="0" stop-color="#0d9488"/><stop offset="1" stop-color="#86cfc5"/></linearGradient>
+    <linearGradient id="grad-arm_r-0" gradientUnits="userSpaceOnUse" x1="171.0" y1="32.3" x2="174.1" y2="29.7"><stop offset="0" stop-color="#0d9488"/><stop offset="1" stop-color="#86cfc5"/></linearGradient>
+  </defs>
   <path d="M 190.0 169.6 L 190.0 141.2 L 130.0 141.2 L 130.0 169.6 Z" fill="none" stroke="#b9bec9" stroke-width="3" stroke-linejoin="round"/>
   <path d="M 160.0 64.0 L 160.0 120.0 L 160.0 120.0 L 160.0 64.0 Z" fill="#c5cad4" stroke="#c5cad4" stroke-width="16" stroke-linecap="round" stroke-linejoin="round"/>
   <path d="M 135.0 131.0 L 185.0 131.0 L 185.0 131.0 L 135.0 131.0 Z" fill="#c5cad4" stroke="#c5cad4" stroke-width="10" stroke-linecap="round" stroke-linejoin="round"/>
   <path d="M 160.0 136.0 L 160.0 150.0" stroke="#c5cad4" stroke-width="6" stroke-linecap="round" stroke-linejoin="round"/>
-  <path id="leg_l" d="M 153.0 116.0 L 153.0 117.6 L 153.0 153.6 L 153.0 148.7" stroke="#a9afba" stroke-width="5" stroke-linecap="round" stroke-linejoin="round"/>
-  <path id="leg_r" d="M 167.0 116.0 L 167.0 117.6 L 167.0 153.6 L 167.0 148.7" stroke="#3a3f4b" stroke-width="6" stroke-linecap="round" stroke-linejoin="round"/>
-  <path id="arm_l" d="M 149.0 32.3 L 145.9 29.7 L 142.8 19.4" stroke="#86cfc5" stroke-width="5" stroke-linecap="round" stroke-linejoin="round"/>
-  <path id="arm_r" d="M 171.0 32.3 L 174.1 29.7 L 177.2 19.4" stroke="#0d9488" stroke-width="6" stroke-linecap="round" stroke-linejoin="round"/>
+  <g id="leg_l">
+    <path d="M 153.0 116.0 L 153.0 117.6" stroke="url(#grad-leg_l-0)" stroke-width="5.5" stroke-linecap="round"/>
+    <path d="M 153.0 117.6 L 153.0 153.6" stroke="#a9afba" stroke-width="5" stroke-linecap="round"/>
+    <path d="M 153.0 153.6 L 153.0 148.7" stroke="#a9afba" stroke-width="5" stroke-linecap="round"/>
+  </g>
+  <g id="leg_r">
+    <path d="M 167.0 116.0 L 167.0 117.6" stroke="url(#grad-leg_r-0)" stroke-width="5.5" stroke-linecap="round"/>
+    <path d="M 167.0 117.6 L 167.0 153.6" stroke="#a9afba" stroke-width="5" stroke-linecap="round"/>
+    <path d="M 167.0 153.6 L 167.0 148.7" stroke="#a9afba" stroke-width="5" stroke-linecap="round"/>
+  </g>
+  <g id="arm_l">
+    <path d="M 149.0 32.3 L 145.9 29.7" stroke="url(#grad-arm_l-0)" stroke-width="5.5" stroke-linecap="round"/>
+    <path d="M 145.9 29.7 L 142.8 19.4" stroke="#86cfc5" stroke-width="5" stroke-linecap="round"/>
+  </g>
+  <g id="arm_r">
+    <path d="M 171.0 32.3 L 174.1 29.7" stroke="url(#grad-arm_r-0)" stroke-width="5.5" stroke-linecap="round"/>
+    <path d="M 174.1 29.7 L 177.2 19.4" stroke="#86cfc5" stroke-width="5" stroke-linecap="round"/>
+  </g>
   <path id="girdle" d="M 149.0 32.3 L 160.0 32.3 L 171.0 32.3" stroke="#3a3f4b" stroke-width="5" stroke-linecap="round" stroke-linejoin="round"/>
   <path id="pelvisBar" d="M 153.0 116.0 L 160.0 116.0 L 167.0 116.0" stroke="#3a3f4b" stroke-width="5" stroke-linecap="round" stroke-linejoin="round"/>
   <path id="spine" d="M 160.0 116.0 Q 160.0 73.2 160.0 32.3" stroke="#3a3f4b" stroke-width="6" stroke-linecap="round" stroke-linejoin="round"/>