feat: Newsletter system improvements and validation framework

- Fix: Marketing events now display in Staff notifications tab
- Reorganize: Move Coupons to Marketing/Coupons for better organization
- Add: Comprehensive email/phone validation with extensible filter hooks
  - Email validation with regex pattern (xxxx@xxxx.xx)
  - Phone validation with WhatsApp verification support
  - Filter hooks for external API integration (QuickEmailVerification, etc.)
- Fix: Newsletter template routes now use centralized notification email builder
- Add: Validation.php class for reusable validation logic
- Add: VALIDATION_HOOKS.md documentation with integration examples
- Add: NEWSLETTER_CAMPAIGN_PLAN.md architecture for future campaign system
- Fix: API delete method call in Newsletter.tsx (delete -> del)
- Remove: Duplicate EmailTemplates.tsx (using notification system instead)
- Update: Newsletter controller to use centralized Validation class

Breaking changes:
- Coupons routes moved from /routes/Coupons to /routes/Marketing/Coupons
- Legacy /coupons routes maintained for backward compatibility

customer-spa/src/hooks/useWishlist.ts

@@ -21,8 +21,9 @@ export function useWishlist() {
   const [isLoading, setIsLoading] = useState(false);
   const [productIds, setProductIds] = useState<Set<number>>(new Set());
   
-  // Check if wishlist is enabled
-  const isEnabled = (window as any).woonoowCustomer?.settings?.wishlist_enabled !== false;
+  // Check if wishlist is enabled (default true if not explicitly set to false)
+  const settings = (window as any).woonoowCustomer?.settings;
+  const isEnabled = settings?.wishlist_enabled !== false;
   const isLoggedIn = (window as any).woonoowCustomer?.user?.isLoggedIn;
 
   // Load wishlist on mount