Enhance API error handling, add lastError tracking, and implement admin home template

public/admin/index.php

@@ -16,7 +16,10 @@ $htmlloader = new HTMLLoader();
 $call = new APICall("auth/isauth.php");
 $response = $call->response;
 
-if (!isset($response["data"]["login"])) {
+if (!$response["data"]["login"]) {
     $htmlloader->setPage("login");
-    $htmlloader->show();
+    $htmlloader->show([], true);
+}else{
+    $htmlloader->setPage("admin_home");
+    $htmlloader->show([], true);
 }