App icon: violet heart + ECG pulse on the dashboard's dark palette

Replaces the Expo template icons; adaptive foreground/monochrome/splash
generated from assets/icon-src/*.svg (rsvg-convert).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

app.json

@@ -9,7 +9,7 @@
     "userInterfaceStyle": "dark",
     "backgroundColor": "#0d0d0f",
     "ios": {
-      "icon": "./assets/expo.icon",
+      "icon": "./assets/images/icon.png",
       "bundleIdentifier": "xyz.rehbock.health",
       "supportsTablet": true
     },