feat(auth): referrer code at signup and agent code in profile

Optional referrer agent code in registration with field validation UX. Show read-only agent referral code in profile edit and desktop overview.

Co-authored-by: Cursor <cursoragent@cursor.com>

src/views/profile/components/DesktopProfilePage.vue

@@ -54,7 +54,9 @@ const checksCount = computed(() => {
 const customerCode = computed(() => {
   const u = auth.user
   if (!u) return toPersianDigits('—')
-  if (auth.isAgent && u.agentCode) return toPersianDigits(u.agentCode)
+  if (auth.isAgent) {
+    return u.agentCode ? toPersianDigits(u.agentCode) : toPersianDigits('—')
+  }
   if (u.nationalId) return toPersianDigits(u.nationalId.slice(-6).padStart(6, '0'))
   return toPersianDigits(u.id?.slice(-6) ?? '—')
 })
@@ -73,7 +75,8 @@ const joinDate = computed(() =>
 
 const creditBalance = computed(() => 0)
 
-const companyRows = computed(() => [
+const companyRows = computed(() => {
+  const rows: Array<{ label: string; value: string; badge?: boolean }> = [
   { label: 'نام شرکت', value: auth.fullName || '—' },
   { label: 'شناسه ملی', value: auth.user?.nationalId ? toPersianDigits(auth.user.nationalId) : '—' },
   {
@@ -87,7 +90,17 @@ const companyRows = computed(() => [
     badge: true,
   },
   { label: 'وضعیت حساب', value: 'فعال', badge: true },
-])
+  ]
+  if (auth.isAgent) {
+    rows.splice(1, 0, {
+      label: 'کد واسطه',
+      value: auth.user?.agentCode
+        ? toPersianDigits(auth.user.agentCode)
+        : '—',
+    })
+  }
+  return rows
+})
 
 const quickAccess = [
   { label: 'حساب‌های بانکی', icon: IconCashSettlement },