Introduce a mobile-friendly phone mode with a bottom navigation bar

Add phone mode functionality with a new bottom navigation component and adjust layout styles for smaller screens. Includes logic for auto-detection and user preference saving for phone mode. Also, redirects authenticated users from `/auth` to the dashboard.

Replit-Commit-Author: Agent
Replit-Commit-Session-Id: 95e8aab4-f39f-4b48-aa57-a759ec15ba3d
Replit-Commit-Checkpoint-Type: intermediate_checkpoint
Replit-Commit-Screenshot-Url: https://storage.googleapis.com/screenshot-production-us-central1/1957c339-2757-4d1f-8e92-e9f71a1ce58e/95e8aab4-f39f-4b48-aa57-a759ec15ba3d/oL3c3As

client/src/components/RouterProduction.tsx

@@ -105,6 +105,17 @@ function RouterProduction() {
         <Route path="/database-debug" component={Utilities} />
         <Route path="/weather-settings" component={Utilities} />
         
+        {/* Redirection depuis /auth vers dashboard après authentification */}
+        <Route path="/auth">
+          {() => {
+            if (typeof window !== 'undefined') {
+              console.log('🔄 Authenticated user on /auth, redirecting to dashboard');
+              window.location.href = '/';
+            }
+            return <Dashboard />;
+          }}
+        </Route>
+        
         <Route path="/" component={Dashboard} />
         <Route component={NotFound} />
       </Switch>