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/dependency-injection/Compiler/ResolveEnvPlaceholdersPass.php

@@ -0,0 +1,46 @@
+<?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\DependencyInjection\Compiler;
+
+use Symfony\Component\DependencyInjection\Definition;
+
+/**
+ * Replaces env var placeholders by their current values.
+ */
+class ResolveEnvPlaceholdersPass extends AbstractRecursivePass
+{
+    protected bool $skipScalars = false;
+
+    protected function processValue(mixed $value, bool $isRoot = false): mixed
+    {
+        if (\is_string($value)) {
+            return $this->container->resolveEnvPlaceholders($value, true);
+        }
+        if ($value instanceof Definition) {
+            $changes = $value->getChanges();
+            if (isset($changes['class'])) {
+                $value->setClass($this->container->resolveEnvPlaceholders($value->getClass(), true));
+            }
+            if (isset($changes['file'])) {
+                $value->setFile($this->container->resolveEnvPlaceholders($value->getFile(), true));
+            }
+        }
+
+        $value = parent::processValue($value, $isRoot);
+
+        if ($value && \is_array($value) && !$isRoot) {
+            $value = array_combine($this->container->resolveEnvPlaceholders(array_keys($value), true), $value);
+        }
+
+        return $value;
+    }
+}