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/Cat-Cow/frames/frame-1.svg

@@ -1,13 +1,33 @@
 <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 180" fill="none">
   <title>Cat-Cow</title>
+  <defs>
+    <linearGradient id="grad-arm_r-0" gradientUnits="userSpaceOnUse" x1="115.3" y1="94.5" x2="120.9" y2="123.5"><stop offset="0" stop-color="#a3a9b4"/><stop offset="1" stop-color="#a9afba"/></linearGradient>
+    <linearGradient id="grad-leg_r-0" gradientUnits="userSpaceOnUse" x1="195.9" y1="106.8" x2="201.5" y2="151.7"><stop offset="0" stop-color="#7b808c"/><stop offset="1" stop-color="#a9afba"/></linearGradient>
+    <linearGradient id="grad-leg_l-2" gradientUnits="userSpaceOnUse" x1="235.6" y1="152.2" x2="244.6" y2="158.4"><stop offset="0" stop-color="#3a3f4b"/><stop offset="1" stop-color="#3b404c"/></linearGradient>
+    <linearGradient id="grad-arm_l-1" gradientUnits="userSpaceOnUse" x1="115.0" y1="125.3" x2="105.0" y2="153.2"><stop offset="0" stop-color="#3a3f4b"/><stop offset="1" stop-color="#404551"/></linearGradient>
+  </defs>
   <path d="M 67.4 160.4 L 262.5 160.4 L 262.5 150.0 L 67.4 150.0 Z" fill="none" stroke="#b9bec9" stroke-width="3" stroke-linejoin="round"/>
-  <path id="arm_r" d="M 115.3 94.5 L 120.9 123.5 L 111.0 151.4" stroke="#a9afba" stroke-width="5" stroke-linecap="round" stroke-linejoin="round"/>
-  <path id="leg_r" d="M 195.9 106.8 L 201.5 151.7 L 241.5 151.7 L 250.5 157.9" stroke="#a9afba" stroke-width="5" stroke-linecap="round" stroke-linejoin="round"/>
-  <path id="leg_l" d="M 190.0 107.2 L 195.6 152.2 L 235.6 152.2 L 244.6 158.4" stroke="#3a3f4b" stroke-width="6" stroke-linecap="round" stroke-linejoin="round"/>
+  <g id="arm_r">
+    <path d="M 115.3 94.5 L 120.9 123.5" stroke="url(#grad-arm_r-0)" stroke-width="5.02758" stroke-linecap="round"/>
+    <path d="M 120.9 123.5 L 111.0 151.4" stroke="#a9afba" stroke-width="5" stroke-linecap="round"/>
+  </g>
+  <g id="leg_r">
+    <path d="M 195.9 106.8 L 201.5 151.7" stroke="url(#grad-leg_r-0)" stroke-width="5.20929" stroke-linecap="round"/>
+    <path d="M 201.5 151.7 L 241.5 151.7" stroke="#a9afba" stroke-width="5" stroke-linecap="round"/>
+    <path d="M 241.5 151.7 L 250.5 157.9" stroke="#a9afba" stroke-width="5" stroke-linecap="round"/>
+  </g>
+  <g id="leg_l">
+    <path d="M 190.0 107.2 L 195.6 152.2" stroke="#3a3f4b" stroke-width="6" stroke-linecap="round"/>
+    <path d="M 195.6 152.2 L 235.6 152.2" stroke="#3a3f4b" stroke-width="6" stroke-linecap="round"/>
+    <path d="M 235.6 152.2 L 244.6 158.4" stroke="url(#grad-leg_l-2)" stroke-width="5.9972" stroke-linecap="round"/>
+  </g>
   <path id="girdle" d="M 109.4 96.3 L 109.4 94.4 L 115.3 94.5" stroke="#0d9488" stroke-width="5" stroke-linecap="round" stroke-linejoin="round"/>
   <path id="pelvisBar" d="M 190.0 107.2 L 190.0 106.0 L 195.9 106.8" stroke="#0d9488" stroke-width="5" stroke-linecap="round" stroke-linejoin="round"/>
   <path id="spine" d="M 190.0 106.0 Q 145.2 123.6 109.4 94.4" stroke="#0d9488" stroke-width="6" stroke-linecap="round" stroke-linejoin="round"/>
-  <path id="arm_l" d="M 109.4 96.3 L 115.0 125.3 L 105.0 153.2" stroke="#3a3f4b" stroke-width="6" stroke-linecap="round" stroke-linejoin="round"/>
+  <g id="arm_l">
+    <path d="M 109.4 96.3 L 115.0 125.3" stroke="#3a3f4b" stroke-width="6" stroke-linecap="round"/>
+    <path d="M 115.0 125.3 L 105.0 153.2" stroke="url(#grad-arm_l-1)" stroke-width="5.9751" stroke-linecap="round"/>
+  </g>
   <circle id="head" cx="89.4" cy="96.1" r="10" fill="white" stroke="#3a3f4b" stroke-width="6"/>
   <line id="nose" x1="79.8" y1="93.4" x2="73.1" y2="91.5" stroke="#3a3f4b" stroke-width="4" stroke-linecap="round"/>
   <g font-family="-apple-system, Helvetica, sans-serif" font-size="11" fill="#6b7180">

Exercise Library/Cat-Cow/frames/frame-2.svg

@@ -1,13 +1,33 @@
 <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 180" fill="none">
   <title>Cat-Cow</title>
+  <defs>
+    <linearGradient id="grad-arm_r-0" gradientUnits="userSpaceOnUse" x1="115.9" y1="96.8" x2="124.6" y2="125.0"><stop offset="0" stop-color="#a4aab5"/><stop offset="1" stop-color="#a9afba"/></linearGradient>
+    <linearGradient id="grad-leg_r-0" gradientUnits="userSpaceOnUse" x1="195.9" y1="106.8" x2="201.5" y2="151.7"><stop offset="0" stop-color="#7b808c"/><stop offset="1" stop-color="#a9afba"/></linearGradient>
+    <linearGradient id="grad-leg_l-2" gradientUnits="userSpaceOnUse" x1="235.6" y1="152.2" x2="244.6" y2="158.4"><stop offset="0" stop-color="#3a3f4b"/><stop offset="1" stop-color="#3b404c"/></linearGradient>
+    <linearGradient id="grad-arm_l-1" gradientUnits="userSpaceOnUse" x1="118.6" y1="126.9" x2="105.0" y2="153.2"><stop offset="0" stop-color="#3a3f4b"/><stop offset="1" stop-color="#3e434f"/></linearGradient>
+  </defs>
   <path d="M 67.4 160.4 L 262.5 160.4 L 262.5 150.0 L 67.4 150.0 Z" fill="none" stroke="#b9bec9" stroke-width="3" stroke-linejoin="round"/>
-  <path id="arm_r" d="M 115.9 96.8 L 124.6 125.0 L 111.0 151.4" stroke="#a9afba" stroke-width="5" stroke-linecap="round" stroke-linejoin="round"/>
-  <path id="leg_r" d="M 195.9 106.8 L 201.5 151.7 L 241.5 151.7 L 250.5 157.9" stroke="#a9afba" stroke-width="5" stroke-linecap="round" stroke-linejoin="round"/>
-  <path id="leg_l" d="M 190.0 107.2 L 195.6 152.2 L 235.6 152.2 L 244.6 158.4" stroke="#3a3f4b" stroke-width="6" stroke-linecap="round" stroke-linejoin="round"/>
+  <g id="arm_r">
+    <path d="M 115.9 96.8 L 124.6 125.0" stroke="url(#grad-arm_r-0)" stroke-width="5.02072" stroke-linecap="round"/>
+    <path d="M 124.6 125.0 L 111.0 151.4" stroke="#a9afba" stroke-width="5" stroke-linecap="round"/>
+  </g>
+  <g id="leg_r">
+    <path d="M 195.9 106.8 L 201.5 151.7" stroke="url(#grad-leg_r-0)" stroke-width="5.20929" stroke-linecap="round"/>
+    <path d="M 201.5 151.7 L 241.5 151.7" stroke="#a9afba" stroke-width="5" stroke-linecap="round"/>
+    <path d="M 241.5 151.7 L 250.5 157.9" stroke="#a9afba" stroke-width="5" stroke-linecap="round"/>
+  </g>
+  <g id="leg_l">
+    <path d="M 190.0 107.2 L 195.6 152.2" stroke="#3a3f4b" stroke-width="6" stroke-linecap="round"/>
+    <path d="M 195.6 152.2 L 235.6 152.2" stroke="#3a3f4b" stroke-width="6" stroke-linecap="round"/>
+    <path d="M 235.6 152.2 L 244.6 158.4" stroke="url(#grad-leg_l-2)" stroke-width="5.9972" stroke-linecap="round"/>
+  </g>
   <path id="girdle" d="M 109.9 98.6 L 109.9 96.7 L 115.9 96.8" stroke="#0d9488" stroke-width="5" stroke-linecap="round" stroke-linejoin="round"/>
   <path id="pelvisBar" d="M 190.0 107.2 L 190.0 106.0 L 195.9 106.8" stroke="#0d9488" stroke-width="5" stroke-linecap="round" stroke-linejoin="round"/>
   <path id="spine" d="M 190.0 106.0 Q 152.1 74.9 109.9 96.7" stroke="#0d9488" stroke-width="6" stroke-linecap="round" stroke-linejoin="round"/>
-  <path id="arm_l" d="M 109.9 98.6 L 118.6 126.9 L 105.0 153.2" stroke="#3a3f4b" stroke-width="6" stroke-linecap="round" stroke-linejoin="round"/>
+  <g id="arm_l">
+    <path d="M 109.9 98.6 L 118.6 126.9" stroke="#3a3f4b" stroke-width="6" stroke-linecap="round"/>
+    <path d="M 118.6 126.9 L 105.0 153.2" stroke="url(#grad-arm_l-1)" stroke-width="5.98377" stroke-linecap="round"/>
+  </g>
   <circle id="head" cx="93.6" cy="108.0" r="10" fill="white" stroke="#3a3f4b" stroke-width="6"/>
   <line id="nose" x1="86.4" y1="115.0" x2="81.5" y2="119.9" stroke="#3a3f4b" stroke-width="4" stroke-linecap="round"/>
   <g font-family="-apple-system, Helvetica, sans-serif" font-size="11" fill="#6b7180">