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/Models/QrDocument.php

@@ -0,0 +1,35 @@
+<?php
+
+namespace App\Models;
+
+use Illuminate\Database\Eloquent\Model;
+use Illuminate\Database\Eloquent\Relations\BelongsTo;
+use Illuminate\Database\Eloquent\Relations\HasMany;
+
+class QrDocument extends Model
+{
+    protected $fillable = [
+        'user_id',
+        'title',
+        'disk',
+        'path',
+        'mime_type',
+        'size_bytes',
+        'page_count',
+    ];
+
+    protected $casts = [
+        'size_bytes' => 'integer',
+        'page_count' => 'integer',
+    ];
+
+    public function user(): BelongsTo
+    {
+        return $this->belongsTo(User::class);
+    }
+
+    public function qrCodes(): HasMany
+    {
+        return $this->hasMany(QrCode::class);
+    }
+}