Enhance API error handling and response structure; update app name retrieval method

api/settings/appname.php

@@ -11,9 +11,8 @@ require_once API_DIR . "api.php";
 $api = new gbAPI(false, $internal);
 
 // Get App Name
-$command = "SELECT name, value FROM settings WHERE name = :name";
-$result = $api->dbCommand($command, true, true, [":name" => "application_name"]);
+$result = $api->getSetting("application_name");
 
 $api->answer(200, [
-    "application_name" => $result[0]["value"]
+    "application_name" => $result
 ]);