add login with enter key

frontend/src/components/LoginPage.tsx

@@ -33,6 +33,15 @@ export default function LoginPage() {
     }
   };
 
+  /**
+   * Catch key events in order to trigger login on enter
+   */
+  const handleKeyDown = (event: React.KeyboardEvent<HTMLInputElement>) => {
+    if (event.key === "Enter") {
+      executeLogin();
+    }
+  };
+
   return (
     <div className="app-bg">
       <div className="flex flex-col gap-3 max-w-sm w-full mx-auto p-6 bg-white rounded-2xl shadow-md">
@@ -43,12 +52,15 @@ export default function LoginPage() {
           placeholder="Benutzername"
           value={userName}
           onChange={(e) => setUserName(e.target.value)}
+          onKeyDown={handleKeyDown}
         />
 
         <PasswordField
             onPasswordChanged = {setPassword}
+            onKeyDown={handleKeyDown}
         />
 
+        {/* error message */}
         {errorMessage && (
           <p className="error-text text-center">{errorMessage}</p>
         )}