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/Child's Pose/frames/frame-1.svg

@@ -1,13 +1,32 @@
 <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 180" fill="none">
   <title>Child's Pose</title>
+  <defs>
+    <linearGradient id="grad-leg_r-0" gradientUnits="userSpaceOnUse" x1="206.9" y1="108.8" x2="209.3" y2="154.0"><stop offset="0" stop-color="#898f9a"/><stop offset="1" stop-color="#a9afba"/></linearGradient>
+    <linearGradient id="grad-leg_l-0" gradientUnits="userSpaceOnUse" x1="201.0" y1="109.2" x2="203.4" y2="154.5"><stop offset="0" stop-color="#3a3f4b"/><stop offset="1" stop-color="#3b404c"/></linearGradient>
+    <linearGradient id="grad-leg_l-1" gradientUnits="userSpaceOnUse" x1="203.4" y1="154.5" x2="241.7" y2="142.9"><stop offset="0" stop-color="#3b404c"/><stop offset="1" stop-color="#3a3f4b"/></linearGradient>
+  </defs>
   <path d="M 66.0 160.5 L 269.8 160.5 L 269.8 150.1 L 66.0 150.1 Z" fill="none" stroke="#b9bec9" stroke-width="3" stroke-linejoin="round"/>
-  <path id="arm_r" d="M 130.4 141.4 L 107.1 160.1 L 80.0 147.5" stroke="#a9afba" stroke-width="5" stroke-linecap="round" stroke-linejoin="round"/>
-  <path id="leg_r" d="M 206.9 108.8 L 209.3 154.0 L 247.6 142.5 L 257.8 146.4" stroke="#a9afba" stroke-width="5" stroke-linecap="round" stroke-linejoin="round"/>
+  <g id="arm_r">
+    <path d="M 130.4 141.4 L 107.1 160.1" stroke="#a9afba" stroke-width="5" stroke-linecap="round"/>
+    <path d="M 107.1 160.1 L 80.0 147.5" stroke="#a9afba" stroke-width="5" stroke-linecap="round"/>
+  </g>
+  <g id="leg_r">
+    <path d="M 206.9 108.8 L 209.3 154.0" stroke="url(#grad-leg_r-0)" stroke-width="5.14391" stroke-linecap="round"/>
+    <path d="M 209.3 154.0 L 247.6 142.5" stroke="#a9afba" stroke-width="5" stroke-linecap="round"/>
+    <path d="M 247.6 142.5 L 257.8 146.4" stroke="#a9afba" stroke-width="5" stroke-linecap="round"/>
+  </g>
   <path id="girdle" d="M 124.5 143.3 L 124.5 141.4 L 130.4 141.4" stroke="#0d9488" stroke-width="5" stroke-linecap="round" stroke-linejoin="round"/>
   <path id="pelvisBar" d="M 201.0 109.2 L 201.0 108.0 L 206.9 108.8" stroke="#0d9488" stroke-width="5" stroke-linecap="round" stroke-linejoin="round"/>
   <path id="spine" d="M 201.0 108.0 Q 155.8 111.8 124.5 141.4" stroke="#0d9488" stroke-width="6" stroke-linecap="round" stroke-linejoin="round"/>
-  <path id="arm_l" d="M 124.5 143.3 L 109.0 168.6 L 84.0 152.3" stroke="#3a3f4b" stroke-width="6" stroke-linecap="round" stroke-linejoin="round"/>
-  <path id="leg_l" d="M 201.0 109.2 L 203.4 154.5 L 241.7 142.9 L 251.9 146.8" stroke="#3a3f4b" stroke-width="6" stroke-linecap="round" stroke-linejoin="round"/>
+  <g id="arm_l">
+    <path d="M 124.5 143.3 L 109.0 168.6" stroke="#3a3f4b" stroke-width="6" stroke-linecap="round"/>
+    <path d="M 109.0 168.6 L 84.0 152.3" stroke="#3a3f4b" stroke-width="6" stroke-linecap="round"/>
+  </g>
+  <g id="leg_l">
+    <path d="M 201.0 109.2 L 203.4 154.5" stroke="url(#grad-leg_l-0)" stroke-width="5.9951" stroke-linecap="round"/>
+    <path d="M 203.4 154.5 L 241.7 142.9" stroke="url(#grad-leg_l-1)" stroke-width="5.9951" stroke-linecap="round"/>
+    <path d="M 241.7 142.9 L 251.9 146.8" stroke="#3a3f4b" stroke-width="6" stroke-linecap="round"/>
+  </g>
   <circle id="head" cx="111.3" cy="156.2" r="10" fill="white" stroke="#3a3f4b" stroke-width="6"/>
   <line id="nose" x1="117.3" y1="164.3" x2="121.4" y2="169.9" stroke="#3a3f4b" stroke-width="4" stroke-linecap="round"/>
   <g font-family="-apple-system, Helvetica, sans-serif" font-size="11" fill="#6b7180">