feat: improve PWA installation experience (#9)

This PR improves the PWA installation experience by enhancing the web
app manifest: - Add scope and orientation settings for better app
behavior - Add app categories (fitness, health, lifestyle) for better
discoverability - Add maskable icon support for better Android
integration and adaptive icons - Keep portrait orientation for optimal
mobile experience - Set prefer_related_applications to false to
encourage PWA installation. These changes will improve how the app
appears and behaves when installed on mobile devices, particularly on
Android.

priv/static/manifest.json

@@ -3,49 +3,61 @@
   "short_name": "GymLive",
   "description": "Track your workouts and progress in real-time",
   "start_url": "/",
+  "scope": "/",
   "display": "standalone",
+  "orientation": "portrait",
   "background_color": "#ffffff",
   "theme_color": "#2563eb",
+  "prefer_related_applications": false,
+  "categories": ["fitness", "health", "lifestyle"],
   "icons": [
     {
       "src": "/images/icons/icon-72x72.png",
       "sizes": "72x72",
-      "type": "image/png"
+      "type": "image/png",
+      "purpose": "any maskable"
     },
     {
       "src": "/images/icons/icon-96x96.png",
       "sizes": "96x96",
-      "type": "image/png"
+      "type": "image/png",
+      "purpose": "any maskable"
     },
     {
       "src": "/images/icons/icon-128x128.png",
       "sizes": "128x128",
-      "type": "image/png"
+      "type": "image/png",
+      "purpose": "any maskable"
     },
     {
       "src": "/images/icons/icon-144x144.png",
       "sizes": "144x144",
-      "type": "image/png"
+      "type": "image/png",
+      "purpose": "any maskable"
     },
     {
       "src": "/images/icons/icon-152x152.png",
       "sizes": "152x152",
-      "type": "image/png"
+      "type": "image/png",
+      "purpose": "any maskable"
     },
     {
       "src": "/images/icons/icon-192x192.png",
       "sizes": "192x192",
-      "type": "image/png"
+      "type": "image/png",
+      "purpose": "any maskable"
     },
     {
       "src": "/images/icons/icon-384x384.png",
       "sizes": "384x384",
-      "type": "image/png"
+      "type": "image/png",
+      "purpose": "any maskable"
     },
     {
       "src": "/images/icons/icon-512x512.png",
       "sizes": "512x512",
-      "type": "image/png"
+      "type": "image/png",
+      "purpose": "any maskable"
     }
   ]
 }