Add Ladill POS v1 — register, Pay checkout, and commerce links.

Staff-facing counter register at pos.ladill.com with catalog cart, cash and
MoMo/card checkout via Ladill Pay, CRM timeline/import, invoice prefill, and
Merchant catalog import.

Co-authored-by: Cursor <cursoragent@cursor.com>

app/Support/LadillAppUrl.php

@@ -0,0 +1,15 @@
+<?php
+
+namespace App\Support;
+
+final class LadillAppUrl
+{
+    public static function connect(string $appSubdomain, string $path = '/'): string
+    {
+        $root = (string) config('app.platform_domain', 'ladill.com');
+        $path = '/'.ltrim($path, '/');
+        $target = "https://{$appSubdomain}.{$root}{$path}";
+
+        return "https://{$appSubdomain}.{$root}/sso/connect?redirect=".urlencode($target);
+    }
+}