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/Service/Test/ServiceLocatorTest.php

@@ -0,0 +1,19 @@
+<?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\Service\Test;
+
+/**
+ * @deprecated since PHPUnit 9.6
+ */
+class ServiceLocatorTest extends ServiceLocatorTestCase
+{
+}

vendor/symfony/contracts/Service/Test/ServiceLocatorTestCase.php

@@ -0,0 +1,97 @@
+<?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\Service\Test;
+
+use PHPUnit\Framework\TestCase;
+use Psr\Container\ContainerExceptionInterface;
+use Psr\Container\ContainerInterface;
+use Psr\Container\NotFoundExceptionInterface;
+use Symfony\Contracts\Service\ServiceLocatorTrait;
+
+abstract class ServiceLocatorTestCase extends TestCase
+{
+    /**
+     * @param array<string, callable> $factories
+     */
+    protected function getServiceLocator(array $factories): ContainerInterface
+    {
+        return new class($factories) implements ContainerInterface {
+            use ServiceLocatorTrait;
+        };
+    }
+
+    public function testHas()
+    {
+        $locator = $this->getServiceLocator([
+            'foo' => static fn () => 'bar',
+            'bar' => static fn () => 'baz',
+            static fn () => 'dummy',
+        ]);
+
+        $this->assertTrue($locator->has('foo'));
+        $this->assertTrue($locator->has('bar'));
+        $this->assertFalse($locator->has('dummy'));
+    }
+
+    public function testGet()
+    {
+        $locator = $this->getServiceLocator([
+            'foo' => static fn () => 'bar',
+            'bar' => static fn () => 'baz',
+        ]);
+
+        $this->assertSame('bar', $locator->get('foo'));
+        $this->assertSame('baz', $locator->get('bar'));
+    }
+
+    public function testGetDoesNotMemoize()
+    {
+        $i = 0;
+        $locator = $this->getServiceLocator([
+            'foo' => static function () use (&$i) {
+                ++$i;
+
+                return 'bar';
+            },
+        ]);
+
+        $this->assertSame('bar', $locator->get('foo'));
+        $this->assertSame('bar', $locator->get('foo'));
+        $this->assertSame(2, $i);
+    }
+
+    public function testThrowsOnUndefinedInternalService()
+    {
+        $locator = $this->getServiceLocator([
+            'foo' => static function () use (&$locator) { return $locator->get('bar'); },
+        ]);
+
+        $this->expectException(NotFoundExceptionInterface::class);
+        $this->expectExceptionMessage('The service "foo" has a dependency on a non-existent service "bar". This locator only knows about the "foo" service.');
+
+        $locator->get('foo');
+    }
+
+    public function testThrowsOnCircularReference()
+    {
+        $locator = $this->getServiceLocator([
+            'foo' => static function () use (&$locator) { return $locator->get('bar'); },
+            'bar' => static function () use (&$locator) { return $locator->get('baz'); },
+            'baz' => static function () use (&$locator) { return $locator->get('bar'); },
+        ]);
+
+        $this->expectException(ContainerExceptionInterface::class);
+        $this->expectExceptionMessage('Circular reference detected for service "bar", path: "bar -> baz -> bar".');
+
+        $locator->get('foo');
+    }
+}