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/UserPushToken.php

@@ -0,0 +1,26 @@
+<?php
+
+namespace App\Models;
+
+use Illuminate\Database\Eloquent\Model;
+use Illuminate\Database\Eloquent\Relations\BelongsTo;
+
+class UserPushToken extends Model
+{
+    protected $fillable = [
+        'user_id',
+        'token',
+        'platform',
+        'device_name',
+        'last_seen_at',
+    ];
+
+    protected $casts = [
+        'last_seen_at' => 'datetime',
+    ];
+
+    public function user(): BelongsTo
+    {
+        return $this->belongsTo(User::class);
+    }
+}