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/exponential-backoff/README.md

@@ -0,0 +1,89 @@
+# exponential-backoff
+
+A utility that allows retrying a function with an exponential delay between attempts.
+
+## Installation
+
+```
+npm i exponential-backoff
+```
+
+## Usage
+
+The `backOff<T>` function takes a promise-returning function to retry, and an optional `BackOffOptions` object. It returns a `Promise<T>`.
+
+```ts
+function backOff<T>(
+  request: () => Promise<T>,
+  options?: BackOffOptions
+): Promise<T>;
+```
+
+Here is an example retrying a function that calls a hypothetical weather endpoint:
+
+```js
+import { backOff } from "exponential-backoff";
+
+function getWeather() {
+  return fetch("weather-endpoint");
+}
+
+async function main() {
+  try {
+    const response = await backOff(() => getWeather());
+    // process response
+  } catch (e) {
+    // handle error
+  }
+}
+
+main();
+```
+
+Migrating across major versions? Here are our [breaking changes](https://github.com/coveo/exponential-backoff/tree/master/doc/migration-guide.md).
+
+### `BackOffOptions`
+
+- `delayFirstAttempt?: boolean`
+
+  Decides whether the `startingDelay` should be applied before the first call. If `false`, the first call will occur without a delay.
+
+  Default value is `false`.
+
+- `jitter?: JitterType | string`
+
+  Decides whether a [jitter](https://aws.amazon.com/blogs/architecture/exponential-backoff-and-jitter/) should be applied to the delay. Possible values are `full` and `none`.
+
+  Default value is `none`.
+
+- `maxDelay?: number`
+
+  The maximum delay, in milliseconds, between two consecutive attempts.
+
+  Default value is `Infinity`.
+
+- `numOfAttempts?: number`
+
+  The maximum number of times to attempt the function.
+
+  Default value is `10`.
+
+  Minimum value is `1`.
+
+- `retry?: (e: any, attemptNumber: number) => boolean | Promise<boolean>`
+
+  The `retry` function can be used to run logic after every failed attempt (e.g. logging a message, assessing the last error, etc.). It is called with the last error and the upcoming attempt number. Returning `true` will retry the function as long as the `numOfAttempts` has not been exceeded. Returning `false` will end the execution.
+
+  Default value is a function that always returns `true`.
+
+- `startingDelay?: number`
+
+  The delay, in milliseconds, before executing the function for the first time.
+
+  Default value is `100` ms.
+
+- `timeMultiple?: number`
+
+  The `startingDelay` is multiplied by the `timeMultiple` to increase the delay between reattempts.
+
+  Default value is `2`.