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/yaml/Resources/bin/yaml-lint

@@ -0,0 +1,49 @@
+#!/usr/bin/env php
+<?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.
+ */
+
+if ('cli' !== \PHP_SAPI) {
+    throw new Exception('This script must be run from the command line.');
+}
+
+/**
+ * Runs the Yaml lint command.
+ *
+ * @author Jan Schädlich <jan.schaedlich@sensiolabs.de>
+ */
+
+use Symfony\Component\Console\Application;
+use Symfony\Component\Yaml\Command\LintCommand;
+
+function includeIfExists(string $file): bool
+{
+    return file_exists($file) && include $file;
+}
+
+if (
+    !includeIfExists(__DIR__ . '/../../../../autoload.php') &&
+    !includeIfExists(__DIR__ . '/../../vendor/autoload.php') &&
+    !includeIfExists(__DIR__ . '/../../../../../../vendor/autoload.php')
+) {
+    fwrite(STDERR, 'Install dependencies using Composer.'.PHP_EOL);
+    exit(1);
+}
+
+if (!class_exists(Application::class)) {
+    fwrite(STDERR, 'You need the "symfony/console" component in order to run the Yaml linter.'.PHP_EOL);
+    exit(1);
+}
+
+(new Application())->add($command = new LintCommand())
+    ->getApplication()
+    ->setDefaultCommand($command->getName(), true)
+    ->run()
+;