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/league/uri-interfaces/IPv4/BCMathCalculator.php

@@ -0,0 +1,85 @@
+<?php
+
+/**
+ * League.Uri (https://uri.thephpleague.com)
+ *
+ * (c) Ignace Nyamagana Butera <nyamsprod@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+declare(strict_types=1);
+
+namespace League\Uri\IPv4;
+
+use function bcadd;
+use function bccomp;
+use function bcdiv;
+use function bcmod;
+use function bcmul;
+use function bcpow;
+use function bcsub;
+use function str_split;
+
+final class BCMathCalculator implements Calculator
+{
+    private const SCALE = 0;
+    private const CONVERSION_TABLE = [
+        '0' => '0', '1' => '1', '2' => '2', '3' => '3',
+        '4' => '4', '5' => '5', '6' => '6', '7' => '7',
+        '8' => '8', '9' => '9', 'a' => '10', 'b' => '11',
+        'c' => '12', 'd' => '13', 'e' => '14', 'f' => '15',
+    ];
+
+    public function baseConvert(mixed $value, int $base): string
+    {
+        $value = (string) $value;
+        if (10 === $base) {
+            return $value;
+        }
+
+        $base = (string) $base;
+        $decimal = '0';
+        foreach (str_split($value) as $char) {
+            $decimal = bcadd($this->multiply($decimal, $base), self::CONVERSION_TABLE[$char], self::SCALE);
+        }
+
+        return $decimal;
+    }
+
+    public function pow(mixed $value, int $exponent): string
+    {
+        return bcpow((string) $value, (string) $exponent, self::SCALE);
+    }
+
+    public function compare(mixed $value1, mixed $value2): int
+    {
+        return bccomp((string) $value1, (string) $value2, self::SCALE);
+    }
+
+    public function multiply(mixed $value1, mixed $value2): string
+    {
+        return bcmul((string) $value1, (string) $value2, self::SCALE);
+    }
+
+    public function div(mixed $value, mixed $base): string
+    {
+        return bcdiv((string) $value, (string) $base, self::SCALE);
+    }
+
+    public function mod(mixed $value, mixed $base): string
+    {
+        return bcmod((string) $value, (string) $base, self::SCALE);
+    }
+
+    public function add(mixed $value1, mixed $value2): string
+    {
+        return bcadd((string) $value1, (string) $value2, self::SCALE);
+    }
+
+    public function sub(mixed $value1, mixed $value2): string
+    {
+        return bcsub((string) $value1, (string) $value2, self::SCALE);
+    }
+}