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/parsica-php/parsica/tests/Parser/AppendTest.php

@@ -0,0 +1,55 @@
+<?php declare(strict_types=1);
+/**
+ * This file is part of the Parsica library.
+ *
+ * Copyright (c) 2020 Mathias Verraes <mathias@verraes.net>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Tests\Parsica\Parsica\Parser;
+
+use Exception;
+use PHPUnit\Framework\TestCase;
+use Parsica\Parsica\PHPUnit\ParserAssertions;
+use Parsica\Parsica\StringStream;
+use function Parsica\Parsica\char;
+
+final class AppendTest extends TestCase
+{
+    use ParserAssertions;
+
+    /** @test */
+    public function append_strings()
+    {
+        $parser = char('a')->append(char('b'));
+        $this->assertParses("abc", $parser, "ab");
+    }
+
+    /** @test */
+    public function append_array()
+    {
+        $a = char('a')->map(fn($x) => [$x]);
+        $b = char('b')->map(fn($x) => [$x]);
+        $this->assertParses("abc", $a->append($b), ['a', 'b']);
+    }
+
+
+    /** @test */
+    public function append_non_semigroup()
+    {
+        $a = char('a')->map(fn($v)=> new NotASemigroup($v));
+        $b = char('b')->map(fn($v)=> new NotASemigroup($v));
+        $this->expectException(Exception::class);
+        $a->append($b)->run(new StringStream('abc'));
+    }
+}
+
+final class NotASemigroup
+{
+
+    public function __construct($_)
+    {
+    }
+}