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/services/platforms/WebPlatformService.ts

@@ -645,17 +645,6 @@ export class WebPlatformService implements PlatformService {
     throw new Error("Camera rotation not implemented in web platform");
   }
 
-  // --- PWA/Web-only methods ---
-  public registerServiceWorker(): void {
-    // PWA service worker is automatically registered by VitePWA plugin
-    // No manual registration needed
-  }
-
-  public get isPWAEnabled(): boolean {
-    // PWA is always enabled for web platform
-    return true;
-  }
-
   /**
    * Checks if running in a worker context
    */