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/xtend/.jshintrc

@@ -0,0 +1,30 @@
+{
+    "maxdepth": 4,
+    "maxstatements": 200,
+    "maxcomplexity": 12,
+    "maxlen": 80,
+    "maxparams": 5,
+
+    "curly": true,
+    "eqeqeq": true,
+    "immed": true,
+    "latedef": false,
+    "noarg": true,
+    "noempty": true,
+    "nonew": true,
+    "undef": true,
+    "unused": "vars",
+    "trailing": true,
+
+    "quotmark": true,
+    "expr": true,
+    "asi": true,
+
+    "browser": false,
+    "esnext": true,
+    "devel": false,
+    "node": false,
+    "nonstandard": false,
+
+    "predef": ["require", "module", "__dirname", "__filename"]
+}