feat: send ticket receipts via WhatsApp and normalize phone numbers

Add WhatsApp API integration for automated receipt delivery
Enforce country codes for all phone number inputs (defaults to +60)

shared/auth.ts

@@ -3,6 +3,7 @@ export const MIN_PASSWORD_LENGTH = 8
 export const MIN_FULL_NAME_LENGTH = 2
 export const USERNAME_PATTERN = /^[a-z0-9._-]{3,32}$/
 export const PHONE_NUMBER_PATTERN = /^\+?\d{8,15}$/
+export const DEFAULT_PHONE_COUNTRY_CODE = '+60'
 
 export type UserRole = 'super_admin' | 'staff'
 
@@ -24,7 +25,21 @@ export function normalizePhoneNumber(value: string) {
   const hasPlusPrefix = trimmed.startsWith('+')
   const digitsOnly = trimmed.replace(/\D/g, '')
 
-  return hasPlusPrefix ? `+${digitsOnly}` : digitsOnly
+  if (!digitsOnly) {
+    return ''
+  }
+
+  if (hasPlusPrefix) {
+    return `+${digitsOnly}`
+  }
+
+  const defaultCountryDigits = DEFAULT_PHONE_COUNTRY_CODE.replace(/\D/g, '')
+
+  if (digitsOnly.startsWith(defaultCountryDigits)) {
+    return `+${digitsOnly}`
+  }
+
+  return `+${defaultCountryDigits}${digitsOnly.replace(/^0+/, '')}`
 }
 
 export function isValidPhoneNumber(value: string) {