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/Goblet Squat/frames/frame-1.svg

@@ -1,13 +1,32 @@
 <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 180" fill="none">
   <title>Goblet Squat</title>
-  <path d="M 142.9 157.6 L 197.4 157.6 L 197.4 150.1 L 142.9 150.1 Z" fill="none" stroke="#b9bec9" stroke-width="2.16" stroke-linejoin="round"/>
-  <path id="leg_l" d="M 164.3 90.6 L 155.0 121.9 L 164.3 148.8 L 156.8 151.3" stroke="#86cfc5" stroke-width="3.6" stroke-linecap="round" stroke-linejoin="round"/>
-  <path id="leg_r" d="M 160.0 91.0 L 151.5 122.5 L 161.4 149.1 L 154.0 151.8" stroke="#0d9488" stroke-width="4.32" stroke-linecap="round" stroke-linejoin="round"/>
-  <path id="arm_l" d="M 169.6 30.1 L 163.7 50.5 L 180.9 37.7" stroke="#a9afba" stroke-width="3.6" stroke-linecap="round" stroke-linejoin="round"/>
+  <defs>
+    <linearGradient id="grad-leg_l-0" gradientUnits="userSpaceOnUse" x1="164.3" y1="90.6" x2="173.6" y2="121.9"><stop offset="0" stop-color="#28a196"/><stop offset="1" stop-color="#86cfc5"/></linearGradient>
+    <linearGradient id="grad-leg_r-1" gradientUnits="userSpaceOnUse" x1="170.1" y1="122.0" x2="161.4" y2="149.1"><stop offset="0" stop-color="#0d9488"/><stop offset="1" stop-color="#2fa499"/></linearGradient>
+    <linearGradient id="grad-leg_r-2" gradientUnits="userSpaceOnUse" x1="161.4" y1="149.1" x2="169.0" y2="151.4"><stop offset="0" stop-color="#2fa499"/><stop offset="1" stop-color="#37a99d"/></linearGradient>
+  </defs>
+  <path d="M 144.2 157.6 L 197.4 157.6 L 197.4 150.1 L 144.2 150.1 Z" fill="none" stroke="#b9bec9" stroke-width="2.16" stroke-linejoin="round"/>
+  <g id="leg_l">
+    <path d="M 164.3 90.6 L 173.6 121.9" stroke="url(#grad-leg_l-0)" stroke-width="3.87943" stroke-linecap="round"/>
+    <path d="M 173.6 121.9 L 164.3 148.8" stroke="#86cfc5" stroke-width="3.6" stroke-linecap="round"/>
+    <path d="M 164.3 148.8 L 171.8 151.3" stroke="#86cfc5" stroke-width="3.6" stroke-linecap="round"/>
+  </g>
+  <g id="leg_r">
+    <path d="M 160.0 91.0 L 170.1 122.0" stroke="#0d9488" stroke-width="4.32" stroke-linecap="round"/>
+    <path d="M 170.1 122.0 L 161.4 149.1" stroke="url(#grad-leg_r-1)" stroke-width="4.21977" stroke-linecap="round"/>
+    <path d="M 161.4 149.1 L 169.0 151.4" stroke="url(#grad-leg_r-2)" stroke-width="4.09468" stroke-linecap="round"/>
+  </g>
+  <g id="arm_l">
+    <path d="M 169.6 30.1 L 163.7 50.5" stroke="#a9afba" stroke-width="3.6" stroke-linecap="round"/>
+    <path d="M 163.7 50.5 L 180.9 37.7" stroke="#a9afba" stroke-width="3.6" stroke-linecap="round"/>
+  </g>
   <path id="girdle" d="M 169.6 30.1 L 165.3 30.0 L 165.3 31.4" stroke="#3a3f4b" stroke-width="3.6" stroke-linecap="round" stroke-linejoin="round"/>
   <path id="pelvisBar" d="M 164.3 90.6 L 160.0 90.1 L 160.0 91.0" stroke="#3a3f4b" stroke-width="3.6" stroke-linecap="round" stroke-linejoin="round"/>
   <path id="spine" d="M 160.0 90.1 Q 162.7 59.4 165.3 30.0" stroke="#3a3f4b" stroke-width="4.32" stroke-linecap="round" stroke-linejoin="round"/>
-  <path id="arm_r" d="M 165.3 31.4 L 161.1 52.3 L 178.0 39.0" stroke="#3a3f4b" stroke-width="4.32" stroke-linecap="round" stroke-linejoin="round"/>
+  <g id="arm_r">
+    <path d="M 165.3 31.4 L 161.1 52.3" stroke="#3a3f4b" stroke-width="4.32" stroke-linecap="round"/>
+    <path d="M 161.1 52.3 L 178.0 39.0" stroke="#3a3f4b" stroke-width="4.32" stroke-linecap="round"/>
+  </g>
   <path d="M 179.4 44.1 L 179.4 32.6" stroke="#6b7180" stroke-width="2.16" stroke-linecap="round" stroke-linejoin="round"/>
   <circle cx="179.4" cy="44.1" r="3.5999999999999996" fill="#6b7180"/>
   <circle cx="179.4" cy="32.6" r="3.5999999999999996" fill="#6b7180"/>