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/utils-merge/index.js

@@ -0,0 +1,23 @@
+/**
+ * Merge object b with object a.
+ *
+ *     var a = { foo: 'bar' }
+ *       , b = { bar: 'baz' };
+ *
+ *     merge(a, b);
+ *     // => { foo: 'bar', bar: 'baz' }
+ *
+ * @param {Object} a
+ * @param {Object} b
+ * @return {Object}
+ * @api public
+ */
+
+exports = module.exports = function(a, b){
+  if (a && b) {
+    for (var key in b) {
+      a[key] = b[key];
+    }
+  }
+  return a;
+};