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/PositionTest.php

@@ -0,0 +1,65 @@
+<?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;
+
+use PHPUnit\Framework\TestCase;
+use Parsica\Parsica\Internal\Position;
+use Parsica\Parsica\StringStream;
+use function Parsica\Parsica\char;
+
+final class PositionTest extends TestCase
+{
+    /** @test */
+    public function update()
+    {
+        $position = Position::initial();
+        $this->assertEquals(1, $position->line());
+        $this->assertEquals(1, $position->column());
+        $position = $position->advance("a");
+        $this->assertEquals(1, $position->line());
+        $this->assertEquals(2, $position->column());
+        $position = $position->advance("\n");
+        $this->assertEquals(2, $position->line());
+        $this->assertEquals(1, $position->column());
+        $position = $position->advance("\n\n\nabc");
+        $this->assertEquals(5, $position->line());
+        $this->assertEquals(4, $position->column());
+    }
+
+    /** @test */
+    public function position_in_sequence()
+    {
+        $parser = char('a')->followedBy(char('b'));
+        $input = new StringStream("abc", Position::initial());
+        $result = $parser->run($input);
+
+        $expectedColumn = 3;
+        $actualColumn = $result->remainder()->position()->column();
+        $this->assertEquals($expectedColumn, $actualColumn);
+    }
+
+    /** @test */
+    public function position_with_tabs()
+    {
+        $expected = 10;
+        // All of these move the column position to 10
+        $position = Position::initial()->advance("123456789");
+        $this->assertEquals($expected, $position->column());
+        $position = Position::initial()->advance("\t56789");
+        $this->assertEquals($expected, $position->column());
+        $position = Position::initial()->advance("\t\t9");
+        $this->assertEquals($expected, $position->column());
+        $position = Position::initial()->advance("1\t56789");
+        $this->assertEquals($expected, $position->column());
+        $position = Position::initial()->advance("123\t56789");
+        $this->assertEquals($expected, $position->column());
+    }
+}