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/squizlabs/php_codesniffer/bin/phpcs

@@ -0,0 +1,15 @@
+#!/usr/bin/env php
+<?php
+/**
+ * PHP_CodeSniffer detects violations of a defined coding standard.
+ *
+ * @author    Greg Sherwood <gsherwood@squiz.net>
+ * @copyright 2006-2015 Squiz Pty Ltd (ABN 77 084 670 600)
+ * @license   https://github.com/PHPCSStandards/PHP_CodeSniffer/blob/HEAD/licence.txt BSD Licence
+ */
+
+require_once __DIR__.'/../autoload.php';
+
+$runner   = new PHP_CodeSniffer\Runner();
+$exitCode = $runner->runPHPCS();
+exit($exitCode);