fix: improve neon theme QR code detectability

- Change neon theme to use white modules on dark green background
- Previous green-on-black had insufficient contrast for QR scanners
- White (#ffffff) on dark green (#001a0d) provides maximum contrast
- Ensures reliable detection by all QR code readers

Author: meabed

src/types/advanced.ts

@@ -334,19 +334,19 @@ export const PRESET_THEMES: Record<string, QRTheme> = {
     style: {
       eyes: {
         frameShape: 'circle',
-        frameColor: '#00ff41',
+        frameColor: '#ffffff',
         frameEffect: 'glow',
         pupilShape: 'circle',
-        pupilColor: '#00ff41',
+        pupilColor: '#ffffff',
         pupilEffect: 'neon',
       },
       body: {
         shape: 'circle',
-        color: '#00ff41',
+        color: '#ffffff',
         effect: 'neon',
       },
       background: {
-        primaryColor: '#000000',
+        primaryColor: '#001a0d',
       },
       effects: {
         glow: {