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/phpunit/php-code-coverage/build/scripts/extract-release-notes.php

@@ -0,0 +1,47 @@
+#!/usr/bin/env php
+<?php declare(strict_types=1);
+if ($argc !== 2) {
+    print $argv[0] . ' <tag>' . PHP_EOL;
+
+    exit(1);
+}
+
+$version       = $argv[1];
+$versionSeries = explode('.', $version)[0] . '.' . explode('.', $version)[1];
+
+$file = __DIR__ . '/../../ChangeLog-' . $versionSeries . '.md';
+
+if (!is_file($file) || !is_readable($file)) {
+    print $file . ' cannot be read' . PHP_EOL;
+
+    exit(1);
+}
+
+$buffer = '';
+$append = false;
+
+foreach (file($file) as $line) {
+    if (str_starts_with($line, '## [' . $version . ']')) {
+        $append = true;
+
+        continue;
+    }
+
+    if ($append && (str_starts_with($line, '## ') || str_starts_with($line, '['))) {
+        break;
+    }
+
+    if ($append) {
+        $buffer .= $line;
+    }
+}
+
+$buffer = trim($buffer);
+
+if ($buffer === '') {
+    print 'Unable to extract release notes' . PHP_EOL;
+
+    exit(1);
+}
+
+print $buffer . PHP_EOL;