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/routing/Requirement/EnumRequirement.php

@@ -0,0 +1,56 @@
+<?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\Routing\Requirement;
+
+use Symfony\Component\Routing\Exception\InvalidArgumentException;
+
+final class EnumRequirement implements \Stringable
+{
+    private string $requirement;
+
+    /**
+     * @template T of \BackedEnum
+     *
+     * @param class-string<T>|list<T> $cases
+     */
+    public function __construct(string|array $cases = [])
+    {
+        if (\is_string($cases)) {
+            if (!is_subclass_of($cases, \BackedEnum::class, true)) {
+                throw new InvalidArgumentException(\sprintf('"%s" is not a "BackedEnum" class.', $cases));
+            }
+
+            $cases = $cases::cases();
+        } else {
+            $class = null;
+
+            foreach ($cases as $case) {
+                if (!$case instanceof \BackedEnum) {
+                    throw new InvalidArgumentException(\sprintf('Case must be a "BackedEnum" instance, "%s" given.', get_debug_type($case)));
+                }
+
+                $class ??= $case::class;
+
+                if (!$case instanceof $class) {
+                    throw new InvalidArgumentException(\sprintf('"%s::%s" is not a case of "%s".', get_debug_type($case), $case->name, $class));
+                }
+            }
+        }
+
+        $this->requirement = implode('|', array_map(static fn ($e) => preg_quote($e->value), $cases));
+    }
+
+    public function __toString(): string
+    {
+        return $this->requirement;
+    }
+}