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/cache/Messenger/EarlyExpirationDispatcher.php

@@ -0,0 +1,64 @@
+<?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\Cache\Messenger;
+
+use Psr\Log\LoggerInterface;
+use Symfony\Component\Cache\Adapter\AdapterInterface;
+use Symfony\Component\Cache\CacheItem;
+use Symfony\Component\DependencyInjection\ReverseContainer;
+use Symfony\Component\Messenger\MessageBusInterface;
+use Symfony\Component\Messenger\Stamp\HandledStamp;
+
+/**
+ * Sends the computation of cached values to a message bus.
+ */
+class EarlyExpirationDispatcher
+{
+    private MessageBusInterface $bus;
+    private ReverseContainer $reverseContainer;
+    private ?\Closure $callbackWrapper;
+
+    public function __construct(MessageBusInterface $bus, ReverseContainer $reverseContainer, ?callable $callbackWrapper = null)
+    {
+        $this->bus = $bus;
+        $this->reverseContainer = $reverseContainer;
+        $this->callbackWrapper = null === $callbackWrapper ? null : $callbackWrapper(...);
+    }
+
+    /**
+     * @return mixed
+     */
+    public function __invoke(callable $callback, CacheItem $item, bool &$save, AdapterInterface $pool, \Closure $setMetadata, ?LoggerInterface $logger = null, ?float $beta = null)
+    {
+        if (!$item->isHit() || null === $message = EarlyExpirationMessage::create($this->reverseContainer, $callback, $item, $pool)) {
+            // The item is stale or the callback cannot be reversed: we must compute the value now
+            $logger?->info('Computing item "{key}" online: '.($item->isHit() ? 'callback cannot be reversed' : 'item is stale'), ['key' => $item->getKey()]);
+
+            return null !== $this->callbackWrapper ? ($this->callbackWrapper)($callback, $item, $save, $pool, $setMetadata, $logger, $beta) : $callback($item, $save);
+        }
+
+        $envelope = $this->bus->dispatch($message);
+
+        if ($logger) {
+            if ($envelope->last(HandledStamp::class)) {
+                $logger->info('Item "{key}" was computed online', ['key' => $item->getKey()]);
+            } else {
+                $logger->info('Item "{key}" sent for recomputation', ['key' => $item->getKey()]);
+            }
+        }
+
+        // The item's value is not stale, no need to write it to the backend
+        $save = false;
+
+        return $message->getItem()->get() ?? $item->get();
+    }
+}