Merge pull request 'Add current user balance display in navbar (CAS-26)' (!49) from task/CAS-26/add-balance-to-nav into main

Reviewed-on: https://git.simonis.lol/projects/casino/pulls/49
Reviewed-by: Klan Jattenhoff <jan@kjan.email>
Reviewed-by: lziemke <lea.z4@schule.bremen.de>

frontend/src/app/shared/components/navbar/navbar.component.html

@@ -11,6 +11,11 @@
       </div>
 
       <div class="hidden md:flex items-center space-x-4">
+        <div
+          class="text-white font-bold bg-deep-blue-contrast rounded-full px-4 py-2 text-sm hover:bg-deep-blue-contrast/80 hover:cursor-pointer hover:scale-105 transition-all active:scale-95 select-none duration-300"
+        >
+          <span>Balance: {{ balance() | currency: 'EUR' : 'symbol' : '1.2-2' }}</span>
+        </div>
         @if (!isLoggedIn) {
           <button (click)="login()" class="button-primary px-4 py-1.5">Anmelden</button>
         }