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/node-addon-api/index.js

@@ -0,0 +1,14 @@
+const path = require('path');
+const { version } = require('./package.json');
+
+const includeDir = path.relative('.', __dirname);
+
+module.exports = {
+  include: `"${__dirname}"`, // deprecated, can be removed as part of 4.0.0
+  include_dir: includeDir,
+  gyp: path.join(includeDir, 'node_api.gyp:nothing'), // deprecated.
+  targets: path.join(includeDir, 'node_addon_api.gyp'),
+  version,
+  isNodeApiBuiltin: true,
+  needsFlag: false
+};