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/@tootallnate/once/dist/index.d.ts

@@ -0,0 +1,14 @@
+/// <reference types="node" />
+import { EventEmitter } from 'events';
+declare function once<T>(emitter: EventEmitter, name: string): once.CancelablePromise<T>;
+declare namespace once {
+    interface CancelFunction {
+        (): void;
+    }
+    interface CancelablePromise<T> extends Promise<T> {
+        cancel: CancelFunction;
+    }
+    type CancellablePromise<T> = CancelablePromise<T>;
+    function spread<T extends any[]>(emitter: EventEmitter, name: string): once.CancelablePromise<T>;
+}
+export = once;