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/event-dispatcher/EventDispatcherInterface.php

@@ -0,0 +1,75 @@
+<?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\EventDispatcher;
+
+use Symfony\Contracts\EventDispatcher\EventDispatcherInterface as ContractsEventDispatcherInterface;
+
+/**
+ * The EventDispatcherInterface is the central point of Symfony's event listener system.
+ * Listeners are registered on the manager and events are dispatched through the
+ * manager.
+ *
+ * @author Bernhard Schussek <bschussek@gmail.com>
+ */
+interface EventDispatcherInterface extends ContractsEventDispatcherInterface
+{
+    /**
+     * Adds an event listener that listens on the specified events.
+     *
+     * @param int $priority The higher this value, the earlier an event
+     *                      listener will be triggered in the chain (defaults to 0)
+     *
+     * @return void
+     */
+    public function addListener(string $eventName, callable $listener, int $priority = 0);
+
+    /**
+     * Adds an event subscriber.
+     *
+     * The subscriber is asked for all the events it is
+     * interested in and added as a listener for these events.
+     *
+     * @return void
+     */
+    public function addSubscriber(EventSubscriberInterface $subscriber);
+
+    /**
+     * Removes an event listener from the specified events.
+     *
+     * @return void
+     */
+    public function removeListener(string $eventName, callable $listener);
+
+    /**
+     * @return void
+     */
+    public function removeSubscriber(EventSubscriberInterface $subscriber);
+
+    /**
+     * Gets the listeners of a specific event or all listeners sorted by descending priority.
+     *
+     * @return array<callable[]|callable>
+     */
+    public function getListeners(?string $eventName = null): array;
+
+    /**
+     * Gets the listener priority for a specific event.
+     *
+     * Returns null if the event or the listener does not exist.
+     */
+    public function getListenerPriority(string $eventName, callable $listener): ?int;
+
+    /**
+     * Checks whether an event has any registered listeners.
+     */
+    public function hasListeners(?string $eventName = null): bool;
+}