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/Standing Calf Raise/frames/frame-1.svg

@@ -1,13 +1,34 @@
 <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 180" fill="none">
   <title>Standing Calf Raise</title>
+  <defs>
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+    <linearGradient id="grad-leg_r-1" gradientUnits="userSpaceOnUse" x1="165.6" y1="122.5" x2="158.6" y2="149.2"><stop offset="0" stop-color="#0d9488"/><stop offset="1" stop-color="#31a59a"/></linearGradient>
+    <linearGradient id="grad-leg_r-2" gradientUnits="userSpaceOnUse" x1="158.6" y1="149.2" x2="166.1" y2="151.1"><stop offset="0" stop-color="#31a59a"/><stop offset="1" stop-color="#38a99e"/></linearGradient>
+    <linearGradient id="grad-arm_l-0" gradientUnits="userSpaceOnUse" x1="166.2" y1="31.9" x2="166.9" y2="52.5"><stop offset="0" stop-color="#a2a8b3"/><stop offset="1" stop-color="#a9afba"/></linearGradient>
+    <linearGradient id="grad-arm_r-1" gradientUnits="userSpaceOnUse" x1="162.8" y1="53.8" x2="165.7" y2="74.3"><stop offset="0" stop-color="#3a3f4b"/><stop offset="1" stop-color="#414652"/></linearGradient>
+  </defs>
   <path d="M 147.7 157.5 L 178.5 157.5 L 178.5 150.2 L 147.7 150.2 Z" fill="none" stroke="#b9bec9" stroke-width="2.1" stroke-linejoin="round"/>
-  <path id="leg_l" d="M 164.1 90.9 L 168.9 122.3 L 161.4 148.9 L 168.8 150.9" stroke="#86cfc5" stroke-width="3.5" stroke-linecap="round" stroke-linejoin="round"/>
-  <path id="leg_r" d="M 160.0 91.3 L 165.6 122.5 L 158.6 149.2 L 166.1 151.1" stroke="#0d9488" stroke-width="4.2" stroke-linecap="round" stroke-linejoin="round"/>
-  <path id="arm_l" d="M 166.2 31.9 L 166.9 52.5 L 169.9 73.0" stroke="#a9afba" stroke-width="3.5" stroke-linecap="round" stroke-linejoin="round"/>
+  <g id="leg_l">
+    <path d="M 164.1 90.9 L 168.9 122.3" stroke="url(#grad-leg_l-0)" stroke-width="3.78058" stroke-linecap="round"/>
+    <path d="M 168.9 122.3 L 161.4 148.9" stroke="#86cfc5" stroke-width="3.5" stroke-linecap="round"/>
+    <path d="M 161.4 148.9 L 168.8 150.9" stroke="#86cfc5" stroke-width="3.5" stroke-linecap="round"/>
+  </g>
+  <g id="leg_r">
+    <path d="M 160.0 91.3 L 165.6 122.5" stroke="#0d9488" stroke-width="4.2" stroke-linecap="round"/>
+    <path d="M 165.6 122.5 L 158.6 149.2" stroke="url(#grad-leg_r-1)" stroke-width="4.09677" stroke-linecap="round"/>
+    <path d="M 158.6 149.2 L 166.1 151.1" stroke="url(#grad-leg_r-2)" stroke-width="3.9732" stroke-linecap="round"/>
+  </g>
+  <g id="arm_l">
+    <path d="M 166.2 31.9 L 166.9 52.5" stroke="url(#grad-arm_l-0)" stroke-width="3.52308" stroke-linecap="round"/>
+    <path d="M 166.9 52.5 L 169.9 73.0" stroke="#a9afba" stroke-width="3.5" stroke-linecap="round"/>
+  </g>
   <path id="girdle" d="M 166.2 31.9 L 162.1 31.8 L 162.1 33.2" stroke="#3a3f4b" stroke-width="3.5" stroke-linecap="round" stroke-linejoin="round"/>
   <path id="pelvisBar" d="M 164.1 90.9 L 160.0 90.4 L 160.0 91.3" stroke="#3a3f4b" stroke-width="3.5" stroke-linecap="round" stroke-linejoin="round"/>
   <path id="spine" d="M 160.0 90.4 Q 161.1 60.4 162.1 31.8" stroke="#3a3f4b" stroke-width="4.2" stroke-linecap="round" stroke-linejoin="round"/>
-  <path id="arm_r" d="M 162.1 33.2 L 162.8 53.8 L 165.7 74.3" stroke="#3a3f4b" stroke-width="4.2" stroke-linecap="round" stroke-linejoin="round"/>
+  <g id="arm_r">
+    <path d="M 162.1 33.2 L 162.8 53.8" stroke="#3a3f4b" stroke-width="4.2" stroke-linecap="round"/>
+    <path d="M 162.8 53.8 L 165.7 74.3" stroke="url(#grad-arm_r-1)" stroke-width="4.17735" stroke-linecap="round"/>
+  </g>
   <circle id="head" cx="163.1" cy="18.1" r="7.0" fill="white" stroke="#3a3f4b" stroke-width="4.2"/>
   <line id="nose" x1="170.1" y1="18.1" x2="175.0" y2="18.1" stroke="#3a3f4b" stroke-width="2.8" stroke-linecap="round"/>
   <g font-family="-apple-system, Helvetica, sans-serif" font-size="11" fill="#6b7180">