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/Hip Thrust/frames/frame-1.svg

@@ -1,18 +1,36 @@
 <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 180" fill="none">
   <title>Hip Thrust</title>
+  <defs>
+    <linearGradient id="grad-leg_l-0" gradientUnits="userSpaceOnUse" x1="155.9" y1="136.8" x2="193.4" y2="110.6"><stop offset="0" stop-color="#86cfc5"/><stop offset="1" stop-color="#71c5ba"/></linearGradient>
+    <linearGradient id="grad-leg_l-1" gradientUnits="userSpaceOnUse" x1="193.4" y1="110.6" x2="207.0" y2="147.6"><stop offset="0" stop-color="#71c5ba"/><stop offset="1" stop-color="#86cfc5"/></linearGradient>
+  </defs>
   <path d="M 32.5 160.9 L 229.8 160.9 L 229.8 150.5 L 32.5 150.5 Z" fill="none" stroke="#b9bec9" stroke-width="3" stroke-linejoin="round"/>
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   <path d="M 68.0 127.0 L 68.0 150.0" stroke="#c5cad4" stroke-width="5" stroke-linecap="round" stroke-linejoin="round"/>
-  <path id="arm_l" d="M 75.2 110.3 L 105.1 108.2 L 128.0 127.2" stroke="#a9afba" stroke-width="5" stroke-linecap="round" stroke-linejoin="round"/>
-  <path id="leg_l" d="M 155.9 136.8 L 193.4 110.6 L 207.0 147.6 L 217.0 143.1" stroke="#86cfc5" stroke-width="5" stroke-linecap="round" stroke-linejoin="round"/>
+  <g id="arm_l">
+    <path d="M 75.2 110.3 L 105.1 108.2" stroke="#a9afba" stroke-width="5" stroke-linecap="round"/>
+    <path d="M 105.1 108.2 L 125.0 86.1" stroke="#a9afba" stroke-width="5" stroke-linecap="round"/>
+  </g>
+  <g id="leg_l">
+    <path d="M 155.9 136.8 L 193.4 110.6" stroke="url(#grad-leg_l-0)" stroke-width="5.08861" stroke-linecap="round"/>
+    <path d="M 193.4 110.6 L 207.0 147.6" stroke="url(#grad-leg_l-1)" stroke-width="5.08861" stroke-linecap="round"/>
+    <path d="M 207.0 147.6 L 217.0 143.1" stroke="#86cfc5" stroke-width="5" stroke-linecap="round"/>
+  </g>
   <path id="girdle" d="M 75.2 110.3 L 69.3 110.2 L 69.3 112.1" stroke="#3a3f4b" stroke-width="5" stroke-linecap="round" stroke-linejoin="round"/>
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   <path id="spine" d="M 150.0 136.0 Q 107.3 127.0 69.3 110.2" stroke="#3a3f4b" stroke-width="6" stroke-linecap="round" stroke-linejoin="round"/>
-  <path id="leg_r" d="M 150.0 137.2 L 187.9 111.6 L 203.0 148.0 L 212.8 143.1" stroke="#0d9488" stroke-width="6" stroke-linecap="round" stroke-linejoin="round"/>
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-  <path d="M 126.0 123.6 L 126.0 132.7" stroke="#6b7180" stroke-width="4" stroke-linecap="round" stroke-linejoin="round"/>
-  <circle cx="126.0" cy="123.6" r="13" fill="#6b7180"/>
-  <circle cx="126.0" cy="132.7" r="13" fill="#6b7180"/>
+  <g id="leg_r">
+    <path d="M 150.0 137.2 L 187.9 111.6" stroke="#0d9488" stroke-width="6" stroke-linecap="round"/>
+    <path d="M 187.9 111.6 L 203.0 148.0" stroke="#0d9488" stroke-width="6" stroke-linecap="round"/>
+    <path d="M 203.0 148.0 L 212.8 143.1" stroke="#0d9488" stroke-width="6" stroke-linecap="round"/>
+  </g>
+  <g id="arm_r">
+    <path d="M 69.3 112.1 L 99.3 112.3" stroke="#3a3f4b" stroke-width="6" stroke-linecap="round"/>
+    <path d="M 99.3 112.3 L 124.2 96.0" stroke="#3a3f4b" stroke-width="6" stroke-linecap="round"/>
+  </g>
+  <path d="M 124.6 86.5 L 124.6 95.5" stroke="#6b7180" stroke-width="4" stroke-linecap="round" stroke-linejoin="round"/>
+  <circle cx="124.6" cy="86.5" r="13" fill="#6b7180"/>
+  <circle cx="124.6" cy="95.5" r="13" fill="#6b7180"/>
   <circle id="head" cx="60.2" cy="92.7" r="10" fill="white" stroke="#3a3f4b" stroke-width="6"/>
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   <g font-family="-apple-system, Helvetica, sans-serif" font-size="11" fill="#6b7180">