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/PlatformService.ts

@@ -207,5 +207,4 @@ export interface PlatformService {
   /**
    * Returns true if PWA is enabled (web only)
    */
-  readonly isPWAEnabled?: boolean;
 }

src/services/platforms/CapacitorPlatformService.ts

@@ -1302,9 +1302,6 @@ export class CapacitorPlatformService implements PlatformService {
 
   // --- PWA/Web-only methods (no-op for Capacitor) ---
   public registerServiceWorker(): void {}
-  public get isPWAEnabled(): boolean {
-    return false;
-  }
 
   // Database utility methods
   generateInsertStatement(

src/services/platforms/ElectronPlatformService.ts

@@ -166,7 +166,4 @@ export class ElectronPlatformService extends CapacitorPlatformService {
 
   // --- PWA/Web-only methods (no-op for Electron) ---
   public registerServiceWorker(): void {}
-  public get isPWAEnabled(): boolean {
-    return false;
-  }
 }

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
    */