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/is-buffer/test/basic.js

@@ -0,0 +1,24 @@
+var isBuffer = require('../')
+var test = require('tape')
+
+test('is-buffer', function (t) {
+  t.equal(isBuffer(Buffer.alloc(4)), true, 'new Buffer(4)')
+  t.equal(isBuffer(Buffer.allocUnsafeSlow(100)), true, 'SlowBuffer(100)')
+
+  t.equal(isBuffer(undefined), false, 'undefined')
+  t.equal(isBuffer(null), false, 'null')
+  t.equal(isBuffer(''), false, 'empty string')
+  t.equal(isBuffer(true), false, 'true')
+  t.equal(isBuffer(false), false, 'false')
+  t.equal(isBuffer(0), false, '0')
+  t.equal(isBuffer(1), false, '1')
+  t.equal(isBuffer(1.0), false, '1.0')
+  t.equal(isBuffer('string'), false, 'string')
+  t.equal(isBuffer({}), false, '{}')
+  t.equal(isBuffer([]), false, '[]')
+  t.equal(isBuffer(function foo () {}), false, 'function foo () {}')
+  t.equal(isBuffer({ isBuffer: null }), false, '{ isBuffer: null }')
+  t.equal(isBuffer({ isBuffer: function () { throw new Error() } }), false, '{ isBuffer: function () { throw new Error() } }')
+
+  t.end()
+})