🐛 Fix PWA install prompt showing after installation

Fixed critical bug where PWA install message continued showing after app installation

- ✅ Enhanced PWA installation status detection
- ✅ Fixed install prompt logic to hide after installation
- ✅ Improved Service Worker update handling
- ✅ Added proper installation state management
- ✅ Enhanced iOS Safari PWA detection
- ✅ Added installation preferences storage

- Added installationChecked flag for better state management
- Enhanced checkInstallationStatus() method with multiple detection methods
- Improved shouldShowPrompt() logic to prevent showing after installation
- Added periodic installation monitoring for iOS devices
- Enhanced Service Worker activation event handling
- Added PWAUtils.checkInstallationStatus() utility method

- public/src/pwa/install-prompt.js (major refactor)
- public/index.html (PWA logic improvements)
- public/sw.js (Service Worker enhancements)

- PWA install message no longer shows after successful installation
- Only update notifications are shown for installed PWAs
- Proper distinction between install prompts and update notifications

Version: Enhanced Security Edition v4.01.413

README.md

@@ -15,7 +15,7 @@
 
 ---
 
-## ✨ What's New in v4.01.412
+## ✨ What's New in v4.01.413
 
 ### 🔒 Comprehensive Connection Security Overhaul
 * **Advanced mutex framework** with 15-second timeout protection
@@ -254,7 +254,7 @@ open http://localhost:8000
 
 ## 🗺️ Development Roadmap
 
-**Current:** v4.01.412 — PWA & File Transfer Edition ✅
+**Current:** v4.01.413 — PWA & File Transfer Edition ✅
 
 * Progressive Web App installation
 * Secure P2P file transfer system
@@ -551,6 +551,6 @@ SecureBit.chat:
 
 ---
 
-**Latest Release: v4.01.412** — PWA & Secure File Transfer
+**Latest Release: v4.01.413** — PWA & Secure File Transfer
 
 </div>