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 Circles/frames/frame-2.svg

@@ -1,13 +1,33 @@
 <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 180" fill="none">
   <title>Hip Circles</title>
+  <defs>
+    <linearGradient id="grad-leg_l-0" gradientUnits="userSpaceOnUse" x1="155.9" y1="92.9" x2="168.5" y2="121.7"><stop offset="0" stop-color="#3a3f4b"/><stop offset="1" stop-color="#a9afba"/></linearGradient>
+    <linearGradient id="grad-leg_r-1" gradientUnits="userSpaceOnUse" x1="157.2" y1="122.6" x2="155.8" y2="150.4"><stop offset="0" stop-color="#3a3f4b"/><stop offset="1" stop-color="#5f6470"/></linearGradient>
+    <linearGradient id="grad-leg_r-2" gradientUnits="userSpaceOnUse" x1="155.8" y1="150.4" x2="163.3" y2="150.6"><stop offset="0" stop-color="#5f6470"/><stop offset="1" stop-color="#8c919d"/></linearGradient>
+    <linearGradient id="grad-arm_l-1" gradientUnits="userSpaceOnUse" x1="161.2" y1="40.5" x2="166.7" y2="41.5"><stop offset="0" stop-color="#a9afba"/><stop offset="1" stop-color="#8a909b"/></linearGradient>
+  </defs>
   <path d="M 112.0 152.5 L 177.7 163.9 L 207.4 158.7 L 141.7 147.3 Z" fill="none" stroke="#b9bec9" stroke-width="2.1" stroke-linejoin="round"/>
-  <path id="leg_l" d="M 155.9 92.9 L 152.2 124.7 L 164.2 149.2 L 157.5 152.8" stroke="#a9afba" stroke-width="3.5" stroke-linecap="round" stroke-linejoin="round"/>
-  <path id="leg_r" d="M 146.0 93.1 L 145.3 125.0 L 155.8 150.4 L 148.8 153.5" stroke="#3a3f4b" stroke-width="4.2" stroke-linecap="round" stroke-linejoin="round"/>
+  <g id="leg_l">
+    <path d="M 155.9 92.9 L 168.5 121.7" stroke="url(#grad-leg_l-0)" stroke-width="3.85" stroke-linecap="round"/>
+    <path d="M 168.5 121.7 L 164.2 149.2" stroke="#a9afba" stroke-width="3.5" stroke-linecap="round"/>
+    <path d="M 164.2 149.2 L 171.6 150.2" stroke="#a9afba" stroke-width="3.5" stroke-linecap="round"/>
+  </g>
+  <g id="leg_r">
+    <path d="M 146.0 93.1 L 157.2 122.6" stroke="#3a3f4b" stroke-width="4.2" stroke-linecap="round"/>
+    <path d="M 157.2 122.6 L 155.8 150.4" stroke="url(#grad-leg_r-1)" stroke-width="4.0849" stroke-linecap="round"/>
+    <path d="M 155.8 150.4 L 163.3 150.6" stroke="url(#grad-leg_r-2)" stroke-width="3.82727" stroke-linecap="round"/>
+  </g>
   <path id="girdle" d="M 149.0 34.8 L 140.8 36.8 L 135.6 39.8" stroke="#0d9488" stroke-width="3.5" stroke-linecap="round" stroke-linejoin="round"/>
   <path id="pelvisBar" d="M 155.9 92.9 L 149.5 92.5 L 146.0 93.1" stroke="#0d9488" stroke-width="3.5" stroke-linecap="round" stroke-linejoin="round"/>
   <path id="spine" d="M 149.5 92.5 Q 147.9 62.7 140.8 36.8" stroke="#0d9488" stroke-width="4.2" stroke-linecap="round" stroke-linejoin="round"/>
-  <path id="arm_l" d="M 149.0 34.8 L 161.2 40.5 L 166.7 41.5" stroke="#a9afba" stroke-width="3.5" stroke-linecap="round" stroke-linejoin="round"/>
-  <path id="arm_r" d="M 135.6 39.8 L 125.9 58.1 L 144.0 51.9" stroke="#3a3f4b" stroke-width="4.2" stroke-linecap="round" stroke-linejoin="round"/>
+  <g id="arm_l">
+    <path d="M 149.0 34.8 L 161.2 40.5" stroke="#a9afba" stroke-width="3.5" stroke-linecap="round"/>
+    <path d="M 161.2 40.5 L 166.7 41.5" stroke="url(#grad-arm_l-1)" stroke-width="3.59807" stroke-linecap="round"/>
+  </g>
+  <g id="arm_r">
+    <path d="M 135.6 39.8 L 125.9 58.1" stroke="#3a3f4b" stroke-width="4.2" stroke-linecap="round"/>
+    <path d="M 125.9 58.1 L 144.0 51.9" stroke="#3a3f4b" stroke-width="4.2" stroke-linecap="round"/>
+  </g>
   <circle id="head" cx="138.1" cy="24.0" r="7.0" fill="white" stroke="#3a3f4b" stroke-width="4.2"/>
   <line id="nose" x1="145.0" y1="25.2" x2="148.4" y2="25.8" stroke="#3a3f4b" stroke-width="2.8" stroke-linecap="round"/>
   <g font-family="-apple-system, Helvetica, sans-serif" font-size="11" fill="#6b7180">