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/Adapter/ParameterNormalizer.php

@@ -0,0 +1,35 @@
+<?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\Adapter;
+
+/**
+ * @author Lars Strojny <lars@strojny.net>
+ */
+final class ParameterNormalizer
+{
+    public static function normalizeDuration(string $duration): int
+    {
+        if (is_numeric($duration)) {
+            return $duration;
+        }
+
+        if (false !== $time = strtotime($duration, 0)) {
+            return $time;
+        }
+
+        try {
+            return \DateTimeImmutable::createFromFormat('U', 0)->add(new \DateInterval($duration))->getTimestamp();
+        } catch (\Exception $e) {
+            throw new \InvalidArgumentException(\sprintf('Cannot parse date interval "%s".', $duration), 0, $e);
+        }
+    }
+}