Enable full PWA install experience in all web modes

- Add PWAInstallPrompt component for custom install UI and event handling
- Register PWAInstallPrompt in App.vue for global visibility
- Enable PWA features and install prompt in dev, test, and prod (vite.config.web.mts)
- Update service worker registration to work in all environments
- Update docs/build-web-script-integration.md with PWA install guidance and visual cues
- Add scripts/build-web.sh for unified web build/dev workflow

PWA is now installable and testable in all web environments, with clear user prompts and desktop support.

vite.config.web.mts

@@ -76,21 +76,40 @@ export default defineConfig(async ({ mode }) => {
 
   return mergeConfig(baseConfig, {
     ...environmentConfig,
+    // Ensure source maps are enabled for development and test modes
+    // This affects both dev server and build output
+    sourcemap: mode === 'development' || mode === 'test',
     // Server configuration inherited from base config
     // CORS headers removed to allow images from any domain
     plugins: [
       VitePWA({
         registerType: 'autoUpdate',
         manifest: appConfig.pwaConfig?.manifest,
+        // Enable PWA in all web environments for consistent testing
         devOptions: {
-          enabled: mode === 'development'
+          enabled: true, // ✅ Enable in all environments
+          type: 'module'
         },
         workbox: {
           cleanupOutdatedCaches: true,
           skipWaiting: true,
           clientsClaim: true,
           sourcemap: mode !== 'production',
-          maximumFileSizeToCacheInBytes: 10 * 1024 * 1024 // 10MB
+          maximumFileSizeToCacheInBytes: 10 * 1024 * 1024, // 10MB
+          // Environment-specific caching strategies
+          runtimeCaching: mode === 'production' ? [
+            {
+              urlPattern: /^https:\/\/api\./,
+              handler: 'NetworkFirst',
+              options: {
+                cacheName: 'api-cache',
+                expiration: {
+                  maxEntries: 100,
+                  maxAgeSeconds: 60 * 60 * 24 // 24 hours
+                }
+              }
+            }
+          ] : []
         }
       })
     ]