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/Dumbbell Fly/visual.svg

@@ -1,16 +1,36 @@
 <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 180" fill="none">
   <title>Dumbbell Fly</title>
+  <defs>
+    <linearGradient id="grad-arm_l-0" gradientUnits="userSpaceOnUse" x1="171.0" y1="101.2" x2="200.8" y2="100.9"><stop offset="0" stop-color="#86cfc5"/><stop offset="1" stop-color="#0d9488"/></linearGradient>
+    <linearGradient id="grad-arm_r-0" gradientUnits="userSpaceOnUse" x1="149.0" y1="101.2" x2="119.2" y2="100.9"><stop offset="0" stop-color="#86cfc5"/><stop offset="1" stop-color="#0d9488"/></linearGradient>
+    <linearGradient id="grad-leg_l-0" gradientUnits="userSpaceOnUse" x1="167.0" y1="116.0" x2="180.8" y2="118.2"><stop offset="0" stop-color="#a9afba"/><stop offset="1" stop-color="#3a3f4b"/></linearGradient>
+    <linearGradient id="grad-leg_r-0" gradientUnits="userSpaceOnUse" x1="153.0" y1="116.0" x2="139.2" y2="116.2"><stop offset="0" stop-color="#a9afba"/><stop offset="1" stop-color="#3a3f4b"/></linearGradient>
+  </defs>
   <path d="M 130.0 141.4 L 130.0 169.4 L 190.0 169.4 L 190.0 141.4 Z" fill="none" stroke="#b9bec9" stroke-width="3" stroke-linejoin="round"/>
   <path d="M 148.0 124.0 L 172.0 124.0 L 172.0 124.0 L 148.0 124.0 Z" fill="#c5cad4" stroke="#c5cad4" stroke-width="8" stroke-linecap="round" stroke-linejoin="round"/>
   <path d="M 154.0 129.0 L 154.0 150.0" stroke="#c5cad4" stroke-width="4" stroke-linecap="round" stroke-linejoin="round"/>
   <path d="M 166.0 129.0 L 166.0 150.0" stroke="#c5cad4" stroke-width="4" stroke-linecap="round" stroke-linejoin="round"/>
-  <path id="arm_l" d="M 171.0 101.2 L 200.8 100.9 L 228.5 89.4" stroke="#0d9488" stroke-width="6" stroke-linecap="round" stroke-linejoin="round"/>
-  <path id="arm_r" d="M 149.0 101.2 L 119.2 100.9 L 91.5 89.4" stroke="#86cfc5" stroke-width="5" stroke-linecap="round" stroke-linejoin="round"/>
+  <g id="arm_l">
+    <path d="M 171.0 101.2 L 200.8 100.9" stroke="url(#grad-arm_l-0)" stroke-width="5.5" stroke-linecap="round"/>
+    <path d="M 200.8 100.9 L 228.5 89.4" stroke="#0d9488" stroke-width="6" stroke-linecap="round"/>
+  </g>
+  <g id="arm_r">
+    <path d="M 149.0 101.2 L 119.2 100.9" stroke="url(#grad-arm_r-0)" stroke-width="5.5" stroke-linecap="round"/>
+    <path d="M 119.2 100.9 L 91.5 89.4" stroke="#0d9488" stroke-width="6" stroke-linecap="round"/>
+  </g>
   <path id="girdle" d="M 171.0 101.2 L 160.0 101.2 L 149.0 101.2" stroke="#3a3f4b" stroke-width="5" stroke-linecap="round" stroke-linejoin="round"/>
   <path id="pelvisBar" d="M 167.0 116.0 L 160.0 116.0 L 153.0 116.0" stroke="#3a3f4b" stroke-width="5" stroke-linecap="round" stroke-linejoin="round"/>
   <path id="spine" d="M 160.0 116.0 Q 160.0 108.4 160.0 101.2" stroke="#3a3f4b" stroke-width="6" stroke-linecap="round" stroke-linejoin="round"/>
-  <path id="leg_l" d="M 167.0 116.0 L 180.8 118.2 L 178.0 158.0 L 181.4 157.6" stroke="#3a3f4b" stroke-width="6" stroke-linecap="round" stroke-linejoin="round"/>
-  <path id="leg_r" d="M 153.0 116.0 L 139.2 116.2 L 142.0 156.1 L 138.7 155.6" stroke="#a9afba" stroke-width="5" stroke-linecap="round" stroke-linejoin="round"/>
+  <g id="leg_l">
+    <path d="M 167.0 116.0 L 180.8 118.2" stroke="url(#grad-leg_l-0)" stroke-width="5.5" stroke-linecap="round"/>
+    <path d="M 180.8 118.2 L 180.8 158.1" stroke="#3a3f4b" stroke-width="6" stroke-linecap="round"/>
+    <path d="M 180.8 158.1 L 184.1 157.7" stroke="#3a3f4b" stroke-width="6" stroke-linecap="round"/>
+  </g>
+  <g id="leg_r">
+    <path d="M 153.0 116.0 L 139.2 116.2" stroke="url(#grad-leg_r-0)" stroke-width="5.5" stroke-linecap="round"/>
+    <path d="M 139.2 116.2 L 139.7 156.1" stroke="#3a3f4b" stroke-width="6" stroke-linecap="round"/>
+    <path d="M 139.7 156.1 L 136.4 155.7" stroke="#3a3f4b" stroke-width="6" stroke-linecap="round"/>
+  </g>
   <path d="M 88.8 95.9 L 94.2 83.0" stroke="#6b7180" stroke-width="3" stroke-linecap="round" stroke-linejoin="round"/>
   <circle cx="88.8" cy="95.9" r="4.5" fill="#6b7180"/>
   <circle cx="94.2" cy="83.0" r="4.5" fill="#6b7180"/>