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/contracts/EventDispatcher/EventDispatcherInterface.php

@@ -0,0 +1,33 @@
+<?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\Contracts\EventDispatcher;
+
+use Psr\EventDispatcher\EventDispatcherInterface as PsrEventDispatcherInterface;
+
+/**
+ * Allows providing hooks on domain-specific lifecycles by dispatching events.
+ */
+interface EventDispatcherInterface extends PsrEventDispatcherInterface
+{
+    /**
+     * Dispatches an event to all registered listeners.
+     *
+     * @template T of object
+     *
+     * @param T           $event     The event to pass to the event handlers/listeners
+     * @param string|null $eventName The name of the event to dispatch. If not supplied,
+     *                               the class of $event should be used instead.
+     *
+     * @return T The passed $event MUST be returned
+     */
+    public function dispatch(object $event, ?string $eventName = null): object;
+}