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/Crunch/visual.svg

@@ -1,13 +1,31 @@
 <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 180" fill="none">
   <title>Crunch</title>
+  <defs>
+    <linearGradient id="grad-leg_l-0" gradientUnits="userSpaceOnUse" x1="171.9" y1="144.8" x2="201.5" y2="110.0"><stop offset="0" stop-color="#a9afba"/><stop offset="1" stop-color="#8e939f"/></linearGradient>
+    <linearGradient id="grad-leg_l-1" gradientUnits="userSpaceOnUse" x1="201.5" y1="110.0" x2="209.0" y2="148.7"><stop offset="0" stop-color="#8e939f"/><stop offset="1" stop-color="#a9afba"/></linearGradient>
+  </defs>
   <path d="M 39.4 161.0 L 231.6 161.0 L 231.6 150.6 L 39.4 150.6 Z" fill="none" stroke="#b9bec9" stroke-width="3" stroke-linejoin="round"/>
-  <path id="leg_l" d="M 171.9 144.8 L 201.5 110.0 L 209.0 148.7 L 219.6 145.8" stroke="#a9afba" stroke-width="5" stroke-linecap="round" stroke-linejoin="round"/>
-  <path id="arm_l" d="M 102.1 103.1 L 95.8 74.2 L 81.8 100.3" stroke="#a9afba" stroke-width="5" stroke-linecap="round" stroke-linejoin="round"/>
+  <g id="leg_l">
+    <path d="M 171.9 144.8 L 201.5 110.0" stroke="url(#grad-leg_l-0)" stroke-width="5.12386" stroke-linecap="round"/>
+    <path d="M 201.5 110.0 L 209.0 148.7" stroke="url(#grad-leg_l-1)" stroke-width="5.12386" stroke-linecap="round"/>
+    <path d="M 209.0 148.7 L 219.6 145.8" stroke="#a9afba" stroke-width="5" stroke-linecap="round"/>
+  </g>
+  <g id="arm_l">
+    <path d="M 102.1 103.1 L 95.8 74.2" stroke="#a9afba" stroke-width="5" stroke-linecap="round"/>
+    <path d="M 95.8 74.2 L 81.8 100.3" stroke="#a9afba" stroke-width="5" stroke-linecap="round"/>
+  </g>
   <path id="girdle" d="M 102.1 103.1 L 96.2 103.0 L 96.2 104.9" stroke="#0d9488" stroke-width="5" stroke-linecap="round" stroke-linejoin="round"/>
   <path id="pelvisBar" d="M 171.9 144.8 L 166.0 144.0 L 166.0 145.2" stroke="#0d9488" stroke-width="5" stroke-linecap="round" stroke-linejoin="round"/>
   <path id="spine" d="M 166.0 144.0 Q 117.5 144.0 96.2 103.0" stroke="#0d9488" stroke-width="6" stroke-linecap="round" stroke-linejoin="round"/>
-  <path id="leg_r" d="M 166.0 145.2 L 195.9 110.8 L 205.0 149.2 L 215.5 145.8" stroke="#3a3f4b" stroke-width="6" stroke-linecap="round" stroke-linejoin="round"/>
-  <path id="arm_r" d="M 96.2 104.9 L 89.9 76.0 L 75.9 102.1" stroke="#3a3f4b" stroke-width="6" stroke-linecap="round" stroke-linejoin="round"/>
+  <g id="leg_r">
+    <path d="M 166.0 145.2 L 195.9 110.8" stroke="#3a3f4b" stroke-width="6" stroke-linecap="round"/>
+    <path d="M 195.9 110.8 L 205.0 149.2" stroke="#3a3f4b" stroke-width="6" stroke-linecap="round"/>
+    <path d="M 205.0 149.2 L 215.5 145.8" stroke="#3a3f4b" stroke-width="6" stroke-linecap="round"/>
+  </g>
+  <g id="arm_r">
+    <path d="M 96.2 104.9 L 89.9 76.0" stroke="#3a3f4b" stroke-width="6" stroke-linecap="round"/>
+    <path d="M 89.9 76.0 L 75.9 102.1" stroke="#3a3f4b" stroke-width="6" stroke-linecap="round"/>
+  </g>
   <circle id="head" cx="92.0" cy="83.8" r="10" fill="white" stroke="#3a3f4b" stroke-width="6"/>
   <line id="nose" x1="101.8" y1="81.7" x2="108.7" y2="80.3" stroke="#3a3f4b" stroke-width="4" stroke-linecap="round"/>
   <g font-family="-apple-system, Helvetica, sans-serif" font-size="11" fill="#6b7180">