v5.0 — PWA Support, Offline Mode, Roadmap Index

What's New

📱 PWA Support

• Add to Home Screen on any device
• Service worker caches all assets for offline use
• App icon, standalone mode

🌐 Offline Mode

• Full offline access to all 17 roadmaps
• Cache-first strategy with background updates
• Offline indicator

📋 Roadmap Index

• Centralized metadata for all roadmaps
• Easier dynamic loading and filtering