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/Internal/FP/FoldrTest.php

@@ -0,0 +1,59 @@
+<?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\Internal\FP;
+
+use PHPUnit\Framework\TestCase;
+use function Parsica\Parsica\Internal\FP\foldr;
+
+final class FoldrTest extends TestCase
+{
+    /** @test */
+    public function sum_implemented_as_foldr()
+    {
+        $actual = foldr([1, 2, 3], fn ($x, $y) => $x + $y, 0);
+        $this->assertSame(6, $actual);
+    }
+
+    /** @test */
+    public function associativity_is_correct()
+    {
+        $minus = fn($x, $y) => $x - $y;
+        $input = [1, 2, 3, 4, 5];
+        $init = 0;
+
+        // foldl: ((((0 - 1) - 2) - 3) - 4) - 5) = -15
+        // foldr: (1 - (2 - (3 - (4 - (5 - 0))))) = 3
+
+        $actual = array_reduce($input, $minus, $init);
+        $this->assertSame(-15, $actual);
+
+        $actual = foldr($input, $minus, $init);
+        $this->assertSame(3, $actual);
+    }
+
+    /** @test */
+    public function x()
+    {
+        $concat = fn($x, $y) => "$x$y";
+        $input = [1, 2, 3, 4, 5];
+        $init = "0";
+
+        // foldl: 012345
+        // foldr: 123450
+
+        $actual = array_reduce($input, $concat, $init);
+        $this->assertSame("012345", $actual);
+
+        $actual = foldr($input, $concat, $init);
+        $this->assertSame("123450", $actual);
+    }
+
+}