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/are-we-there-yet/lib/tracker-base.js

@@ -0,0 +1,11 @@
+'use strict'
+var EventEmitter = require('events').EventEmitter
+var util = require('util')
+
+var trackerId = 0
+var TrackerBase = module.exports = function (name) {
+  EventEmitter.call(this)
+  this.id = ++trackerId
+  this.name = name
+}
+util.inherits(TrackerBase, EventEmitter)