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/Definition/Builder/EnumNodeDefinition.php

@@ -0,0 +1,52 @@
+<?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\Definition\Builder;
+
+use Symfony\Component\Config\Definition\EnumNode;
+
+/**
+ * Enum Node Definition.
+ *
+ * @author Johannes M. Schmitt <schmittjoh@gmail.com>
+ */
+class EnumNodeDefinition extends ScalarNodeDefinition
+{
+    private array $values;
+
+    /**
+     * @return $this
+     */
+    public function values(array $values): static
+    {
+        if (!$values) {
+            throw new \InvalidArgumentException('->values() must be called with at least one value.');
+        }
+
+        $this->values = $values;
+
+        return $this;
+    }
+
+    /**
+     * Instantiate a Node.
+     *
+     * @throws \RuntimeException
+     */
+    protected function instantiateNode(): EnumNode
+    {
+        if (!isset($this->values)) {
+            throw new \RuntimeException('You must call ->values() on enum nodes.');
+        }
+
+        return new EnumNode($this->name, $this->parent, $this->values, $this->pathSeparator);
+    }
+}