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/Examples/CalculatorTest.php

@@ -0,0 +1,63 @@
+<?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\Examples;
+
+use PHPUnit\Framework\TestCase;
+use Parsica\Parsica\Parser;
+use function Parsica\Parsica\{atLeastOne, between, char, digitChar, keepFirst, recursive, skipHSpace, string};
+use function Parsica\Parsica\Expression\{binaryOperator,
+    expression,
+    leftAssoc,
+    postfix,
+    prefix,
+    unaryOperator};
+
+/**
+ * Parse expressions and calculate the result
+ */
+final class CalculatorTest extends TestCase
+{
+    /** @test */
+    public function calculator()
+    {
+        $token = fn(Parser $parser) => keepFirst($parser, skipHSpace());
+        $parens = fn (Parser $parser): Parser =>  $token(between($token(char('(')), $token(char(')')), $parser));
+        $term = fn(): Parser => $token(atLeastOne(digitChar()));
+
+        $expr = recursive();
+        $expr->recurse(expression(
+            $parens($expr)->or($term()),
+            [
+                prefix(
+                    unaryOperator(char('-'), fn($v) => -$v),
+                    unaryOperator(char('+'), fn($v) => $v),
+                ),
+                postfix(
+                    unaryOperator($token(string('--')), fn($v) => $v - 1),
+                    unaryOperator($token(string('++')), fn($v) => $v + 1),
+                ),
+                leftAssoc(
+                    binaryOperator($token(char('*')), fn($l, $r) => $l * $r),
+                    binaryOperator($token(char('/')), fn($l, $r) => $l / $r),
+                ),
+                leftAssoc(
+                    binaryOperator($token(char('+')), fn($l, $r) => $l + $r),
+                    binaryOperator($token(char('-')), fn($l, $r) => $l - $r),
+                ),
+            ]
+        ));
+
+
+        $parser = $expr->thenEof();
+        $result = $parser->tryString("(3 - 2) + -1 - 3 * (1 + 1) / 6");
+        $this->assertEquals(-1, (string)$result->output());
+    }
+}