chore: update kirby-seo plugin to v2.0.0-alpha.12

Update plugin from v1.1.2 to v2.0.0-alpha.12 for Kirby 5 compatibility.

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

site/plugins/kirby-seo/classes/Seo.php

@@ -0,0 +1,29 @@
+<?php
+
+namespace tobimori\Seo;
+
+use Kirby\Cms\App;
+
+final class Seo
+{
+	/**
+	 * Returns the user agent string for the plugin
+	 */
+	public static function userAgent(): string
+	{
+		return "Kirby SEO/" . App::plugin('tobimori/seo')->version() . " (+https://plugins.andkindness.com/seo)";
+	}
+
+	/**
+	 * Returns a plugin option
+	 */
+	public static function option(string $key, mixed $default = null, mixed $args = []): mixed
+	{
+		$option = App::instance()->option("tobimori.seo.{$key}", $default);
+		if (is_callable($option)) {
+			$option = $option(...$args);
+		}
+
+		return $option;
+	}
+}