feat(smart-app): implement complete mobile app MVP

- App.tsx: full navigation (Auth stack + Main tabs with 5 screens)
- Auth: LoginScreen, RegisterScreen, ForgotPasswordScreen
- HomeScreen: dashboard with IoT metrics, weather widget, alerts, quick actions, sensors
- MapScreen: interactive map with layer toggles (6 layers)
- MarketplaceScreen: categories (6), products (5), search
- ChatScreen: AI chat with quick prompts (4), bot responses
- ProfileScreen: user info, stats, menu (9 items), logout
- AlertsScreen: alert list with severity, acknowledge
- SensorsScreen: sensor list with type filters (6 types), search
- ZonesScreen: zone cards with stats
- SettingsScreen: language picker (FR/EN/ES/DE), privacy, about
- Stores: iotStore (sensors, zones, alerts), notificationStore, uiStore + i18n
- Hooks: useSensors, useAlerts, useNotifications, useLocation
- Components: Card, Button, LoadingSpinner, ErrorBoundary, Header
- Services: iotService, notificationService (with axios API client)
- Utils: formatters (temp, AQI, noise, dates), validators (email, password, IBAN)
- Theme: colors.ts with full design system (Blue Ocean palette)
- Ditto: fixed MongoDB connection, new JWT secrets, official gateway image

smart-app-city/frontend/node_modules/fbjs/lib/flattenArray.js

@@ -0,0 +1,47 @@
+"use strict";
+
+/**
+ * Copyright (c) 2013-present, Facebook, Inc.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @typechecks
+ * 
+ */
+
+/**
+ * Returns a flattened array that represents the DFS traversal of the supplied
+ * input array. For example:
+ *
+ *   var deep = ["a", ["b", "c"], "d", {"e": [1, 2]}, [["f"], "g"]];
+ *   var flat = flattenArray(deep);
+ *   console.log(flat);
+ *   > ["a", "b", "c", "d", {"e": [1, 2]}, "f", "g"];
+ *
+ * @see https://github.com/jonschlinkert/arr-flatten
+ * @copyright 2014-2015 Jon Schlinkert
+ * @license MIT
+ */
+function flattenArray(array) {
+  var result = [];
+  flatten(array, result);
+  return result;
+}
+
+function flatten(array, result) {
+  var length = array.length;
+  var ii = 0;
+
+  while (length--) {
+    var current = array[ii++];
+
+    if (Array.isArray(current)) {
+      flatten(current, result);
+    } else {
+      result.push(current);
+    }
+  }
+}
+
+module.exports = flattenArray;