Fixes the configuration file

app/Configs/Content.php

@@ -0,0 +1,74 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Configs;
+
+use Illuminate\Support\Arr;
+use Laravel\Nova\Fields\Markdown;
+
+/**
+ * Config Field class for the "content" config group.
+ * Defines fields, defaults, and Nova fields for content settings.
+ */
+final class Content
+{
+    public string $title = 'Content';
+
+    public string $description = 'Content settings';
+
+    public string $key = 'content';
+
+    /**
+     * Returns the field definitions with their type and default value for this config group.
+     */
+    public function getFieldKeys(): array
+    {
+        return [
+            'disclaimer' => [
+                'type' => 'markdown',
+                'default' => '',
+            ],
+        ];
+    }
+
+    /**
+     * Returns the default value for the given field key, or null if the key does not exist.
+     */
+    public function getDefault(string $key): mixed
+    {
+        $fields = $this->getFieldKeys();
+
+        if (! Arr::has($fields, $key)) {
+            return null;
+        }
+
+        return Arr::get($fields, "{$key}.default");
+    }
+
+    /**
+     * Returns Nova field instances for this config group, each wired with
+     * resolveUsing (read from json_value with default fallback) and
+     * fillUsing (write back into json_value) callbacks.
+     */
+    public function getNovaFields(): array
+    {
+        return [
+            Markdown::make('Disclaimer', 'disclaimer')
+                ->resolveUsing(function (mixed $value, mixed $resource): string {
+                    $jsonValue = Arr::get((array) $resource->json_value, 'disclaimer');
+
+                    if ($jsonValue === null || $jsonValue === '') {
+                        return (string) $this->getDefault('disclaimer');
+                    }
+
+                    return (string) $jsonValue;
+                })
+                ->fillUsing(function (mixed $request, mixed $model, string $attribute, string $requestAttribute): void {
+                    $current = Arr::wrap((array) $model->json_value);
+                    Arr::set($current, $attribute, $request->{$requestAttribute});
+                    $model->json_value = $current;
+                }),
+        ];
+    }
+}