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/graphql/validation/rules/ExecutableDefinitionsRule.js.flow

@@ -0,0 +1,39 @@
+// @flow strict
+import { GraphQLError } from '../../error/GraphQLError';
+
+import type { ASTVisitor } from '../../language/visitor';
+import { Kind } from '../../language/kinds';
+import { isExecutableDefinitionNode } from '../../language/predicates';
+
+import type { ASTValidationContext } from '../ValidationContext';
+
+/**
+ * Executable definitions
+ *
+ * A GraphQL document is only valid for execution if all definitions are either
+ * operation or fragment definitions.
+ */
+export function ExecutableDefinitionsRule(
+  context: ASTValidationContext,
+): ASTVisitor {
+  return {
+    Document(node) {
+      for (const definition of node.definitions) {
+        if (!isExecutableDefinitionNode(definition)) {
+          const defName =
+            definition.kind === Kind.SCHEMA_DEFINITION ||
+            definition.kind === Kind.SCHEMA_EXTENSION
+              ? 'schema'
+              : '"' + definition.name.value + '"';
+          context.reportError(
+            new GraphQLError(
+              `The ${defName} definition is not executable.`,
+              definition,
+            ),
+          );
+        }
+      }
+      return false;
+    },
+  };
+}