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/mkdirp-classic/README.md

@@ -0,0 +1,18 @@
+# mkdirp-classic
+
+Just a non-deprecated mirror of [mkdirp 0.5.2](https://github.com/substack/node-mkdirp/tree/0.5.1)
+for use in modules where we depend on the non promise interface.
+
+```
+npm install mkdirp-classic
+```
+
+## Usage
+
+``` js
+// See the above link
+```
+
+## License
+
+MIT