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/Barbell Squat/frames/frame-1.svg

@@ -1,16 +1,35 @@
 <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 180" fill="none">
   <title>Barbell Squat</title>
+  <defs>
+    <linearGradient id="grad-leg_l-0" gradientUnits="userSpaceOnUse" x1="164.1" y1="90.9" x2="169.8" y2="122.1"><stop offset="0" stop-color="#25a094"/><stop offset="1" stop-color="#86cfc5"/></linearGradient>
+    <linearGradient id="grad-leg_r-1" gradientUnits="userSpaceOnUse" x1="166.4" y1="122.3" x2="160.0" y2="149.2"><stop offset="0" stop-color="#0d9488"/><stop offset="1" stop-color="#31a69a"/></linearGradient>
+    <linearGradient id="grad-leg_r-2" gradientUnits="userSpaceOnUse" x1="160.0" y1="149.2" x2="167.5" y2="150.9"><stop offset="0" stop-color="#31a69a"/><stop offset="1" stop-color="#37a99d"/></linearGradient>
+  </defs>
   <path d="M 121.5 157.5 L 193.9 157.5 L 193.9 150.2 L 121.5 150.2 Z" fill="none" stroke="#b9bec9" stroke-width="2.1" stroke-linejoin="round"/>
-  <path id="leg_l" d="M 164.1 90.9 L 169.8 122.1 L 162.8 148.9 L 170.3 150.7" stroke="#86cfc5" stroke-width="3.5" stroke-linecap="round" stroke-linejoin="round"/>
-  <path id="leg_r" d="M 160.0 91.3 L 153.6 122.3 L 160.0 149.2 L 152.5 150.9" stroke="#0d9488" stroke-width="4.2" stroke-linecap="round" stroke-linejoin="round"/>
-  <path id="arm_l" d="M 170.4 32.2 L 183.1 48.6 L 167.0 35.3" stroke="#a9afba" stroke-width="3.5" stroke-linecap="round" stroke-linejoin="round"/>
+  <g id="leg_l">
+    <path d="M 164.1 90.9 L 169.8 122.1" stroke="url(#grad-leg_l-0)" stroke-width="3.77978" stroke-linecap="round"/>
+    <path d="M 169.8 122.1 L 162.8 148.9" stroke="#86cfc5" stroke-width="3.5" stroke-linecap="round"/>
+    <path d="M 162.8 148.9 L 170.3 150.7" stroke="#86cfc5" stroke-width="3.5" stroke-linecap="round"/>
+  </g>
+  <g id="leg_r">
+    <path d="M 160.0 91.3 L 166.4 122.3" stroke="#0d9488" stroke-width="4.2" stroke-linecap="round"/>
+    <path d="M 166.4 122.3 L 160.0 149.2" stroke="url(#grad-leg_r-1)" stroke-width="4.09597" stroke-linecap="round"/>
+    <path d="M 160.0 149.2 L 167.5 150.9" stroke="url(#grad-leg_r-2)" stroke-width="3.97337" stroke-linecap="round"/>
+  </g>
+  <g id="arm_l">
+    <path d="M 170.4 32.2 L 183.1 48.6" stroke="#a9afba" stroke-width="3.5" stroke-linecap="round"/>
+    <path d="M 183.1 48.6 L 174.3 29.8" stroke="#a9afba" stroke-width="3.5" stroke-linecap="round"/>
+  </g>
   <path id="girdle" d="M 170.4 32.2 L 166.2 32.1 L 166.2 33.5" 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 163.2 60.6 166.2 32.1" stroke="#3a3f4b" stroke-width="4.2" stroke-linecap="round" stroke-linejoin="round"/>
-  <path id="arm_r" d="M 166.2 33.5 L 182.9 46.1 L 164.2 36.6" stroke="#3a3f4b" stroke-width="4.2" stroke-linecap="round" stroke-linejoin="round"/>
-  <path d="M 165.6 32.8 L 165.6 39.1" stroke="#6b7180" stroke-width="2.8" stroke-linecap="round" stroke-linejoin="round"/>
-  <circle cx="165.6" cy="32.8" r="9.799999999999999" fill="#6b7180"/>
-  <circle cx="165.6" cy="39.1" r="9.799999999999999" fill="#6b7180"/>
+  <g id="arm_r">
+    <path d="M 166.2 33.5 L 182.9 46.1" stroke="#3a3f4b" stroke-width="4.2" stroke-linecap="round"/>
+    <path d="M 182.9 46.1 L 168.8 30.7" stroke="#3a3f4b" stroke-width="4.2" stroke-linecap="round"/>
+  </g>
+  <path d="M 171.6 27.1 L 171.6 33.4" stroke="#6b7180" stroke-width="2.8" stroke-linecap="round" stroke-linejoin="round"/>
+  <circle cx="171.6" cy="27.1" r="9.799999999999999" fill="#6b7180"/>
+  <circle cx="171.6" cy="33.4" r="9.799999999999999" fill="#6b7180"/>
   <circle id="head" cx="168.2" cy="18.5" r="7.0" fill="white" stroke="#3a3f4b" stroke-width="4.2"/>
   <line id="nose" x1="175.2" y1="18.7" x2="180.1" y2="18.9" stroke="#3a3f4b" stroke-width="2.8" stroke-linecap="round"/>
   <g font-family="-apple-system, Helvetica, sans-serif" font-size="11" fill="#6b7180">