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/package.json

@@ -0,0 +1,19 @@
+{
+  "name": "marketing-app-server",
+  "version": "1.0.0",
+  "description": "Marketing Management App Backend",
+  "main": "server.js",
+  "scripts": {
+    "start": "node server.js",
+    "dev": "node --watch server.js"
+  },
+  "dependencies": {
+    "bcrypt": "^6.0.0",
+    "better-sqlite3": "^11.7.0",
+    "connect-sqlite3": "^0.9.16",
+    "cors": "^2.8.5",
+    "express": "^4.21.0",
+    "express-session": "^1.19.0",
+    "multer": "^1.4.5-lts.1"
+  }
+}