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/sebastian/comparator/README.md

@@ -0,0 +1,41 @@
+# sebastian/comparator
+
+[![CI Status](https://github.com/sebastianbergmann/comparator/workflows/CI/badge.svg)](https://github.com/sebastianbergmann/comparator/actions)
+[![Type Coverage](https://shepherd.dev/github/sebastianbergmann/comparator/coverage.svg)](https://shepherd.dev/github/sebastianbergmann/comparator)
+
+This component provides the functionality to compare PHP values for equality.
+
+## Installation
+
+You can add this library as a local, per-project dependency to your project using [Composer](https://getcomposer.org/):
+
+```
+composer require sebastian/comparator
+```
+
+If you only need this library during development, for instance to run your project's test suite, then you should add it as a development-time dependency:
+
+```
+composer require --dev sebastian/comparator
+```
+
+## Usage
+
+```php
+<?php
+use SebastianBergmann\Comparator\Factory;
+use SebastianBergmann\Comparator\ComparisonFailure;
+
+$date1 = new DateTime('2013-03-29 04:13:35', new DateTimeZone('America/New_York'));
+$date2 = new DateTime('2013-03-29 03:13:35', new DateTimeZone('America/Chicago'));
+
+$factory = new Factory;
+$comparator = $factory->getComparatorFor($date1, $date2);
+
+try {
+    $comparator->assertEquals($date1, $date2);
+    print "Dates match";
+} catch (ComparisonFailure $failure) {
+    print "Dates don't match";
+}
+```