Marketing Hub: RBAC, i18n (AR/EN), tasks overhaul, team/user merge, tutorial

Features:
- Full RBAC with 3 roles (superadmin/manager/contributor)
- Ownership tracking on posts, tasks, campaigns, projects
- Task system: assign to anyone, filter combobox, visibility scoping
- Team members merged into users table (single source of truth)
- Post thumbnails on kanban cards from attachments
- Publication link validation before publishing
- Interactive onboarding tutorial with Settings restart
- Full Arabic/English i18n with RTL layout support
- Language toggle in sidebar, IBM Plex Sans Arabic font
- Brand-based visibility filtering for non-superadmins
- Manager can only create contributors
- Profile completion flow for new users
- Cookie-based sessions (express-session + SQLite)

server/node_modules/expand-template/index.js

@@ -0,0 +1,26 @@
+module.exports = function (opts) {
+  var sep = opts ? opts.sep : '{}'
+  var len = sep.length
+
+  var whitespace = '\\s*'
+  var left = escape(sep.substring(0, len / 2)) + whitespace
+  var right = whitespace + escape(sep.substring(len / 2, len))
+
+  return function (template, values) {
+    Object.keys(values).forEach(function (key) {
+      var value = String(values[key]).replace(/\$/g, '$$$$')
+      template = template.replace(regExp(key), value)
+    })
+    return template
+  }
+
+  function escape (s) {
+    return [].map.call(s, function (char) {
+      return '\\' + char
+    }).join('')
+  }
+
+  function regExp (key) {
+    return new RegExp(left + key + right, 'g')
+  }
+}