feat(batch-1): multi-role sidebar, video display, certificate layout, upload progress, counselor access

- roleMenuItems.js: merged menu builder that unions items from all user roles
  (student + missionary, student + counselor, etc.) additively
- auth store: expose `roles` array in addition to singular `role`; wire in
  WordPress auth-status cookie sync so the public site can show/hide the
  account button
- router guards: use roles.includes() instead of role === for multi-role access
- layouts (Student/Counselor/Missionary): delegate menuItems to
  buildMergedMenuItems so dual-role users see sections from both roles
- StudentSessionDetailsPage: contentKind now returns 'video' (not 'link')
  when session.videoUrl is set; adds embed iframe branch for online sessions
- CertificateItem.vue: fix CSS order/alignment for desktop + mobile layout
- StudentCertificatesPage.vue: map backend payload fields to component props
  with Jalaali date formatting
- SessionFormPage: upload progress bar (%) during video uploads; embed_code
  textarea for online sessions (frontend-only; dormant until batch-2 backend
  migration is deployed)
- wp-sync/auth-status-cookie.js: cookie helper for WordPress login-state sync

[batch-1-low-risk]

src/router/guards.js

@@ -33,7 +33,7 @@ export const statusGuard = (to) => {
   if (!tokenService.hasToken()) return
   const auth = useAuthStore()
   if (!auth.user) return
-  if (auth.role && auth.role !== 'student') return
+  if (!auth.roles.includes('student')) return
   if (auth.user.status === 'approved') return
   return { name: 'student-register' }
 }
@@ -41,7 +41,7 @@ export const statusGuard = (to) => {
 export const roleGuard = (to) => {
   if (!to.meta?.role) return
   const auth = useAuthStore()
-  if (auth.role !== to.meta.role) {
+  if (!auth.roles.includes(to.meta.role)) {
     return { name: 'home' }
   }
   return