Fix layout names to match exact TradingView account names

- Use exact layout names: 'ai' and 'Diy module' (as in TradingView)
- Update default selected layouts to ['ai', 'Diy module']
- Keep display names exactly as they appear in TradingView
- Add lowercase fallback mapping in backend for 'diy module'
- Remove normalization that was changing the exact names

This ensures UI shows exactly what's in the TradingView account and selection state matches display.

lib/enhanced-screenshot.ts

@@ -17,7 +17,8 @@ export interface ScreenshotConfig {
 const LAYOUT_URLS = {
   'ai': 'Z1TzpUrf',
   'diy': 'vWVvjLhP',
-  'Diy module': 'vWVvjLhP' // Alternative mapping for 'Diy module'
+  'Diy module': 'vWVvjLhP', // Exact TradingView name
+  'diy module': 'vWVvjLhP'  // Lowercase fallback
 }
 
 export class EnhancedScreenshotService {