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/Dip/frames/frame-1.svg

@@ -1,15 +1,34 @@
 <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 180" fill="none">
   <title>Dip</title>
+  <defs>
+    <linearGradient id="grad-leg_l-0" gradientUnits="userSpaceOnUse" x1="164.6" y1="101.1" x2="186.2" y2="129.3"><stop offset="0" stop-color="#8a909b"/><stop offset="1" stop-color="#a9afba"/></linearGradient>
+    <linearGradient id="grad-arm_l-0" gradientUnits="userSpaceOnUse" x1="173.8" y1="35.9" x2="168.3" y2="58.3"><stop offset="0" stop-color="#7fccc2"/><stop offset="1" stop-color="#86cfc5"/></linearGradient>
+    <linearGradient id="grad-arm_r-1" gradientUnits="userSpaceOnUse" x1="164.4" y1="59.9" x2="170.9" y2="82.0"><stop offset="0" stop-color="#0d9488"/><stop offset="1" stop-color="#14978b"/></linearGradient>
+  </defs>
   <path d="M 137.7 158.4 L 207.6 158.4 L 207.6 150.2 L 137.7 150.2 Z" fill="none" stroke="#b9bec9" stroke-width="2.34" stroke-linejoin="round"/>
   <path d="M 172.5 84.9 L 172.5 150.4" stroke="#c5cad4" stroke-width="3.9000000000000004" stroke-linecap="round" stroke-linejoin="round"/>
   <circle cx="172.5" cy="81.0" r="2.73" fill="#6b7180"/>
-  <path id="leg_l" d="M 164.6 101.1 L 186.2 129.3 L 155.0 127.7 L 151.7 135.5" stroke="#a9afba" stroke-width="3.9" stroke-linecap="round" stroke-linejoin="round"/>
-  <path id="arm_l" d="M 173.8 35.9 L 168.3 58.3 L 174.0 80.6" stroke="#86cfc5" stroke-width="3.9" stroke-linecap="round" stroke-linejoin="round"/>
-  <path id="leg_r" d="M 160.0 101.5 L 181.6 129.7 L 150.4 128.1 L 147.1 135.9" stroke="#3a3f4b" stroke-width="4.68" stroke-linecap="round" stroke-linejoin="round"/>
+  <g id="leg_l">
+    <path d="M 164.6 101.1 L 186.2 129.3" stroke="url(#grad-leg_l-0)" stroke-width="4.00772" stroke-linecap="round"/>
+    <path d="M 186.2 129.3 L 155.0 127.7" stroke="#a9afba" stroke-width="3.9" stroke-linecap="round"/>
+    <path d="M 155.0 127.7 L 151.7 135.5" stroke="#a9afba" stroke-width="3.9" stroke-linecap="round"/>
+  </g>
+  <g id="arm_l">
+    <path d="M 173.8 35.9 L 168.3 58.3" stroke="url(#grad-arm_l-0)" stroke-width="3.92183" stroke-linecap="round"/>
+    <path d="M 168.3 58.3 L 174.0 80.6" stroke="#86cfc5" stroke-width="3.9" stroke-linecap="round"/>
+  </g>
+  <g id="leg_r">
+    <path d="M 160.0 101.5 L 181.6 129.7" stroke="#3a3f4b" stroke-width="4.68" stroke-linecap="round"/>
+    <path d="M 181.6 129.7 L 150.4 128.1" stroke="#3a3f4b" stroke-width="4.68" stroke-linecap="round"/>
+    <path d="M 150.4 128.1 L 147.1 135.9" stroke="#3a3f4b" stroke-width="4.68" stroke-linecap="round"/>
+  </g>
   <path id="girdle" d="M 173.8 35.9 L 169.2 35.9 L 169.2 37.4" stroke="#3a3f4b" stroke-width="3.9" stroke-linecap="round" stroke-linejoin="round"/>
   <path id="pelvisBar" d="M 164.6 101.1 L 160.0 100.5 L 160.0 101.5" stroke="#3a3f4b" stroke-width="3.9" stroke-linecap="round" stroke-linejoin="round"/>
   <path id="spine" d="M 160.0 100.5 Q 164.7 67.4 169.2 35.9" stroke="#3a3f4b" stroke-width="4.68" stroke-linecap="round" stroke-linejoin="round"/>
-  <path id="arm_r" d="M 169.2 37.4 L 164.4 59.9 L 170.9 82.0" stroke="#0d9488" stroke-width="4.68" stroke-linecap="round" stroke-linejoin="round"/>
+  <g id="arm_r">
+    <path d="M 169.2 37.4 L 164.4 59.9" stroke="#0d9488" stroke-width="4.68" stroke-linecap="round"/>
+    <path d="M 164.4 59.9 L 170.9 82.0" stroke="url(#grad-arm_r-1)" stroke-width="4.65877" stroke-linecap="round"/>
+  </g>
   <circle id="head" cx="172.7" cy="20.9" r="7.800000000000001" fill="white" stroke="#3a3f4b" stroke-width="4.68"/>
   <line id="nose" x1="180.5" y1="21.3" x2="186.0" y2="21.6" stroke="#3a3f4b" stroke-width="3.12" stroke-linecap="round"/>
   <g font-family="-apple-system, Helvetica, sans-serif" font-size="11" fill="#6b7180">