Fixed DTLS Race Condition & Memory Safety

✅ FIXED HIGH CRITICALITY vulnerabilities (October 2024):
- DTLS ClientHello Race Condition: Added source validation
- Memory Safety Issues: Enhanced secure memory cleanup
- Added DTLS protection constants and validation methods
- Improved memory cleanup with secureWipe and zero-filling
- Integrated DTLS protection in handleSecureAnswer

sw.js

@@ -1,5 +1,5 @@
 // SecureBit.chat Service Worker
-// Enhanced Security Edition v4.01.413
+// Enhanced Security Edition v4.01.441
 
 const CACHE_NAME = 'securebit-v4.0.3';
 const STATIC_CACHE = 'securebit-static-v4.0.3';
@@ -361,4 +361,4 @@ self.addEventListener('unhandledrejection', (event) => {
     console.error('❌ Service Worker unhandled rejection:', event.reason);
 });
 
-console.log('🔧 SecureBit.chat Service Worker loaded - Enhanced Security Edition v4.01.413');
+console.log('🔧 SecureBit.chat Service Worker loaded - Enhanced Security Edition v4.01.441');