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/better-sqlite3/deps/test_extension.c

@@ -0,0 +1,21 @@
+#include <sqlite3ext.h>
+SQLITE_EXTENSION_INIT1
+
+/*
+	This SQLite extension is used only for testing purposes (npm test).
+ */
+
+static void TestExtensionFunction(sqlite3_context* pCtx, int nVal, sqlite3_value** _) {
+	sqlite3_result_double(pCtx, (double)nVal);
+}
+
+#ifdef _WIN32
+__declspec(dllexport)
+#endif
+
+int sqlite3_extension_init(sqlite3* db, char** pzErrMsg, const sqlite3_api_routines* pApi) {
+	SQLITE_EXTENSION_INIT2(pApi)
+	if (pzErrMsg != 0) *pzErrMsg = 0;
+	sqlite3_create_function(db, "testExtensionFunction", -1, SQLITE_UTF8, 0, TestExtensionFunction, 0, 0);
+	return SQLITE_OK;
+}