Add multi-branch POS with team roles and branch-scoped cashiers.

Pro and Business users can manage branches, invite cashiers with branch assignment, and switch registers; sales and register flows respect acting location.

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

app/Models/PosMember.php

@@ -0,0 +1,38 @@
+<?php
+
+namespace App\Models;
+
+use Illuminate\Database\Eloquent\Builder;
+use Illuminate\Database\Eloquent\Model;
+use Illuminate\Database\Eloquent\Relations\BelongsTo;
+
+class PosMember extends Model
+{
+    public const ROLE_ADMIN = 'admin';
+
+    public const ROLE_MANAGER = 'manager';
+
+    public const ROLE_CASHIER = 'cashier';
+
+    protected $fillable = [
+        'owner_ref',
+        'user_ref',
+        'role',
+        'location_id',
+    ];
+
+    public function location(): BelongsTo
+    {
+        return $this->belongsTo(PosLocation::class, 'location_id');
+    }
+
+    public function hasRole(string ...$roles): bool
+    {
+        return in_array($this->role, $roles, true);
+    }
+
+    public function scopeOwned(Builder $query, string $ownerRef): Builder
+    {
+        return $query->where('owner_ref', $ownerRef);
+    }
+}