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/RewindableGenerator.php

@@ -0,0 +1,43 @@
+<?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;
+
+/**
+ * @internal
+ */
+class RewindableGenerator implements \IteratorAggregate, \Countable
+{
+    private \Closure $generator;
+    private \Closure|int $count;
+
+    public function __construct(callable $generator, int|callable $count)
+    {
+        $this->generator = $generator(...);
+        $this->count = \is_int($count) ? $count : $count(...);
+    }
+
+    public function getIterator(): \Traversable
+    {
+        $g = $this->generator;
+
+        return $g();
+    }
+
+    public function count(): int
+    {
+        if (!\is_int($count = $this->count)) {
+            $this->count = $count();
+        }
+
+        return $this->count;
+    }
+}