initial COmmit: Add KB Antora Importer plugin files

kb-antora-importer/includes/Frontend/TemplateLoader.php

@@ -0,0 +1,28 @@
+<?php
+declare(strict_types=1);
+
+namespace KbAntoraImporter\Frontend;
+
+final class TemplateLoader
+{
+    public function render(string $template, array $vars = []): void
+    {
+        $path = KB_ANTORA_IMPORTER_DIR . 'templates/' . $template . '.php';
+
+        if (! is_readable($path)) {
+            status_header(500);
+            echo esc_html__('Knowledgebase template missing.', 'kb-antora-importer');
+            return;
+        }
+
+        extract($vars, EXTR_SKIP);
+        include $path;
+    }
+
+    public function capture(string $template, array $vars = []): string
+    {
+        ob_start();
+        $this->render($template, $vars);
+        return (string) ob_get_clean();
+    }
+}