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/Adapter/Polyfill/StreamedWritingTrait.php

@@ -0,0 +1,60 @@
+<?php
+
+namespace League\Flysystem\Adapter\Polyfill;
+
+use League\Flysystem\Config;
+use League\Flysystem\Util;
+
+trait StreamedWritingTrait
+{
+    /**
+     * Stream fallback delegator.
+     *
+     * @param string   $path
+     * @param resource $resource
+     * @param Config   $config
+     * @param string   $fallback
+     *
+     * @return mixed fallback result
+     */
+    protected function stream($path, $resource, Config $config, $fallback)
+    {
+        Util::rewindStream($resource);
+        $contents = stream_get_contents($resource);
+        $fallbackCall = [$this, $fallback];
+
+        return call_user_func($fallbackCall, $path, $contents, $config);
+    }
+
+    /**
+     * Write using a stream.
+     *
+     * @param string   $path
+     * @param resource $resource
+     * @param Config   $config
+     *
+     * @return mixed false or file metadata
+     */
+    public function writeStream($path, $resource, Config $config)
+    {
+        return $this->stream($path, $resource, $config, 'write');
+    }
+
+    /**
+     * Update a file using a stream.
+     *
+     * @param string   $path
+     * @param resource $resource
+     * @param Config   $config   Config object or visibility setting
+     *
+     * @return mixed false of file metadata
+     */
+    public function updateStream($path, $resource, Config $config)
+    {
+        return $this->stream($path, $resource, $config, 'update');
+    }
+
+    // Required abstract methods
+    abstract public function write($pash, $contents, Config $config);
+    abstract public function update($pash, $contents, Config $config);
+}