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/league/flysystem/src/Plugin/ListFiles.php

@@ -0,0 +1,35 @@
+<?php
+
+namespace League\Flysystem\Plugin;
+
+class ListFiles extends AbstractPlugin
+{
+    /**
+     * Get the method name.
+     *
+     * @return string
+     */
+    public function getMethod()
+    {
+        return 'listFiles';
+    }
+
+    /**
+     * List all files in the directory.
+     *
+     * @param string $directory
+     * @param bool   $recursive
+     *
+     * @return array
+     */
+    public function handle($directory = '', $recursive = false)
+    {
+        $contents = $this->filesystem->listContents($directory, $recursive);
+
+        $filter = function ($object) {
+            return $object['type'] === 'file';
+        };
+
+        return array_values(array_filter($contents, $filter));
+    }
+}