refactor: Cleanup git state - commit all staged changes

Major refactoring cleanup:
- Add new controller architecture (class-controller-*.php)
- Add new settings-v2 UI (views/settings-v2/)
- Add new CSS architecture (agentic-sidebar.css, tokens)
- Add esbuild build pipeline (scripts/build.js, package.json)
- Add composer dependencies (vendor/)
- Add frontend src directory (assets/js/src/index.jsx)
- Add documentation files
- Remove old/obsolete files (class-settings.php, old CSS)

This commits all pending changes from previous refactoring efforts.

vendor/symfony/config/ResourceCheckerConfigCacheFactory.php

@@ -0,0 +1,41 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Config;
+
+/**
+ * A ConfigCacheFactory implementation that validates the
+ * cache with an arbitrary set of ResourceCheckers.
+ *
+ * @author Matthias Pigulla <mp@webfactory.de>
+ */
+class ResourceCheckerConfigCacheFactory implements ConfigCacheFactoryInterface
+{
+    private iterable $resourceCheckers = [];
+
+    /**
+     * @param iterable<int, ResourceCheckerInterface> $resourceCheckers
+     */
+    public function __construct(iterable $resourceCheckers = [])
+    {
+        $this->resourceCheckers = $resourceCheckers;
+    }
+
+    public function cache(string $file, callable $callable): ConfigCacheInterface
+    {
+        $cache = new ResourceCheckerConfigCache($file, $this->resourceCheckers);
+        if (!$cache->isFresh()) {
+            $callable($cache);
+        }
+
+        return $cache;
+    }
+}