Make the app logo and favicon match smartphone app icon styles

Update the logo image className in App.tsx to include rounded-lg for a softer, app-icon-like appearance.

Replit-Commit-Author: Agent
Replit-Commit-Session-Id: ceced2fc-aa46-458d-ba87-ddd4b7bb1518
Replit-Commit-Checkpoint-Type: full_checkpoint
Replit-Commit-Screenshot-Url: https://storage.googleapis.com/screenshot-production-us-central1/659922a9-0087-461c-90dd-6d9a58b81d4d/ceced2fc-aa46-458d-ba87-ddd4b7bb1518/E3NLe8e

client/src/App.tsx

@@ -370,7 +370,7 @@ function App() {
                 <img 
                   src={logoImage} 
                   alt="TaskFlow Logo" 
-                  className="w-8 h-8 object-contain"
+                  className="w-8 h-8 object-contain rounded-lg"
                   data-testid="img-app-logo"
                 />
                 <h1 className="text-lg font-semibold" data-testid="text-app-title">