Remove PWA functionality and service worker infrastructure

Completely remove Progressive Web App features including VitePWA plugin, service workers, install prompts, and platform service PWA methods. Delete PWA component, service worker files, help images, and update build configurations. Simplify application architecture by removing PWA complexity while maintaining core functionality.

src/views/HelpNotificationsView.vue

@@ -88,12 +88,7 @@
           To be notified of interesting updates, install this app on your device
           (as opposed to using it inside the browser app). In Chrome, it may prompt
           you, and you can also look for the "Install" command in the browser
-          settings; on the the desktop, look for this icon in the address bar:
-          <img
-            src="../assets/help/chrome-install-pwa.png"
-            alt="Chrome 'install' icon"
-            class="ml-4"
-          />
+          settings.
         </p>
       </div>