feat: Add Progressive Web App (PWA) support

[ecapuano]

Summary

• Adds full PWA support to DetectionForge, allowing users to install it as a standalone application
• Maintains internet connectivity requirement (no offline mode) as the app depends on LimaCharlie API

Changes

• ✅ Installed and configured vite-plugin-pwa for automated PWA generation
• ✅ Enhanced manifest.json with complete PWA properties
• ✅ Added PWA-specific meta tags for cross-platform support
• ✅ Implemented custom install prompt component with smart dismissal
• ✅ Configured service worker for static asset caching only
• ✅ Added debugging tools for PWA troubleshooting
• ✅ Created icon generation scripts for future use

Benefits

• Installable: Users can install DetectionForge like a native app
• Faster Loading: Static assets are cached for improved performance
• Native Experience: Runs in standalone window without browser chrome
• Auto Updates: Service worker handles seamless updates
• Cross-Platform: Works on Windows, macOS, Linux, iOS, and Android

Testing

• Tested PWA installation in development mode
• Verified service worker registration and caching
• Confirmed install prompt behavior
• Validated manifest and meta tags

Notes

• Current icons use SVG fallback; PNG icons can be generated using provided scripts
• No offline functionality as the app requires API connectivity
• Install prompt respects user dismissal with 7-day cooldown