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/Http/Middleware/SetActingAccount.php

@@ -0,0 +1,41 @@
+<?php
+
+namespace App\Http\Middleware;
+
+use App\Models\User;
+use Closure;
+use Illuminate\Http\Request;
+use Illuminate\Support\Facades\View;
+use Symfony\Component\HttpFoundation\Response;
+
+class SetActingAccount
+{
+    public function handle(Request $request, Closure $next): Response
+    {
+        if ($user = $request->user()) {
+            if ($request->is('api/*')) {
+                $accountId = (int) ($request->header('X-Ladill-Account') ?: $user->id);
+            } else {
+                $accountId = (int) $request->session()->get('ladill_account', $user->id);
+            }
+
+            if (! $user->canAccessAccount($accountId)) {
+                $accountId = $user->id;
+                if (! $request->is('api/*')) {
+                    $request->session()->put('ladill_account', $accountId);
+                }
+            }
+
+            $account = $accountId === $user->id ? $user : (User::find($accountId) ?? $user);
+
+            $request->attributes->set('actingAccount', $account);
+
+            if (! $request->is('api/*')) {
+                View::share('actingAccount', $account);
+                View::share('accessibleAccounts', $user->accessibleAccounts());
+            }
+        }
+
+        return $next($request);
+    }
+}