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/http-client/Response/ResponseStream.php

@@ -0,0 +1,52 @@
+<?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\HttpClient\Response;
+
+use Symfony\Contracts\HttpClient\ChunkInterface;
+use Symfony\Contracts\HttpClient\ResponseInterface;
+use Symfony\Contracts\HttpClient\ResponseStreamInterface;
+
+/**
+ * @author Nicolas Grekas <p@tchwork.com>
+ */
+final class ResponseStream implements ResponseStreamInterface
+{
+    public function __construct(
+        private \Generator $generator,
+    ) {
+    }
+
+    public function key(): ResponseInterface
+    {
+        return $this->generator->key();
+    }
+
+    public function current(): ChunkInterface
+    {
+        return $this->generator->current();
+    }
+
+    public function next(): void
+    {
+        $this->generator->next();
+    }
+
+    public function rewind(): void
+    {
+        $this->generator->rewind();
+    }
+
+    public function valid(): bool
+    {
+        return $this->generator->valid();
+    }
+}