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/dependency-injection/Argument/ReferenceSetArgumentTrait.php

@@ -0,0 +1,60 @@
+<?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\DependencyInjection\Argument;
+
+trigger_deprecation('symfony/dependency-injection', '6.1', '"%s" is deprecated.', ReferenceSetArgumentTrait::class);
+
+use Symfony\Component\DependencyInjection\Exception\InvalidArgumentException;
+use Symfony\Component\DependencyInjection\Reference;
+
+/**
+ * @author Titouan Galopin <galopintitouan@gmail.com>
+ * @author Nicolas Grekas <p@tchwork.com>
+ *
+ * @deprecated since Symfony 6.1
+ */
+trait ReferenceSetArgumentTrait
+{
+    private array $values;
+
+    /**
+     * @param Reference[] $values
+     */
+    public function __construct(array $values)
+    {
+        $this->setValues($values);
+    }
+
+    /**
+     * @return Reference[]
+     */
+    public function getValues(): array
+    {
+        return $this->values;
+    }
+
+    /**
+     * @param Reference[] $values The service references to put in the set
+     *
+     * @return void
+     */
+    public function setValues(array $values)
+    {
+        foreach ($values as $k => $v) {
+            if (null !== $v && !$v instanceof Reference) {
+                throw new InvalidArgumentException(\sprintf('A "%s" must hold only Reference instances, "%s" given.', __CLASS__, get_debug_type($v)));
+            }
+        }
+
+        $this->values = $values;
+    }
+}