feat(client): add PWA support

[Copilot]

The client app had no PWA capabilities — no manifest, no service worker, no installability.

Changes

• vite-plugin-pwa — added as dev dependency; configured in vite.config.ts with autoUpdate registration mode
• Web App Manifest — standalone display, theme/background color #1e143c, correct icon entries (192, 512, 512 maskable)
• Service Worker — Workbox generateSW precaches all JS/CSS/HTML/assets; cache-first strategy for Google Fonts (1-year TTL)
• Icons — added public/pwa-192x192.png, public/pwa-512x512.png, public/apple-touch-icon.png (180px for iOS)
• index.html — added theme-color meta, description meta, and apple-touch-icon link

// vite.config.ts
VitePWA({
    registerType: 'autoUpdate',
    manifest: {
        name: 'Chat E2EE - Minimal & Secure',
        short_name: 'Chat E2EE',
        display: 'standalone',
        theme_color: '#1e143c',
        icons: [/* 192, 512, 512 maskable */],
    },
    workbox: {
        globPatterns: ['**/*.{js,css,html,ico,png,svg,woff2}'],
        runtimeCaching: [/* Google Fonts cache-first, 1yr TTL */],
    },
})

[muke1908]

@copilot resolve conflicts

[Copilot]

@copilot resolve conflicts

Conflicts resolved in edf6772. The only conflict was package-lock.json — merged master's changes and regenerated the lock file to include both the upstream updates and the vite-plugin-pwa dependency. Build passes ✅.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud