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/var-exporter/Exception/ClassNotFoundException.php

@@ -0,0 +1,20 @@
+<?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\VarExporter\Exception;
+
+class ClassNotFoundException extends \Exception implements ExceptionInterface
+{
+    public function __construct(string $class, ?\Throwable $previous = null)
+    {
+        parent::__construct(\sprintf('Class "%s" not found.', $class), 0, $previous);
+    }
+}

vendor/symfony/var-exporter/Exception/ExceptionInterface.php

@@ -0,0 +1,16 @@
+<?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\VarExporter\Exception;
+
+interface ExceptionInterface extends \Throwable
+{
+}

vendor/symfony/var-exporter/Exception/LogicException.php

@@ -0,0 +1,16 @@
+<?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\VarExporter\Exception;
+
+class LogicException extends \LogicException implements ExceptionInterface
+{
+}

vendor/symfony/var-exporter/Exception/NotInstantiableTypeException.php

@@ -0,0 +1,20 @@
+<?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\VarExporter\Exception;
+
+class NotInstantiableTypeException extends \Exception implements ExceptionInterface
+{
+    public function __construct(string $type, ?\Throwable $previous = null)
+    {
+        parent::__construct(\sprintf('Type "%s" is not instantiable.', $type), 0, $previous);
+    }
+}