feat: multi-tenant SaaS implementation - admin interface, tenant isolation, and UI updates

app/Traits/BelongsToTenant.php

@@ -0,0 +1,38 @@
+<?php
+
+namespace App\Traits;
+
+use Illuminate\Database\Eloquent\Builder;
+use Illuminate\Support\Facades\Auth;
+
+trait BelongsToTenant
+{
+    protected static function bootBelongsToTenant()
+    {
+        static::addGlobalScope('tenant', function (Builder $builder) {
+            if (Auth::check()) {
+                $user = Auth::user();
+
+                if ($user->role === 'super_admin') {
+                    // Super admins see everything
+                    return;
+                }
+
+                if ($user->tenant_id) {
+                    $builder->where('tenant_id', $user->tenant_id);
+                }
+            }
+        });
+
+        static::creating(function ($model) {
+            if (Auth::check() && Auth::user()->tenant_id && Auth::user()->role !== 'super_admin') {
+                $model->tenant_id = Auth::user()->tenant_id;
+            }
+        });
+    }
+
+    public function tenant()
+    {
+        return $this->belongsTo(\App\Models\Tenant::class);
+    }
+}