Copy tarifas and promos on user registration

When a new user registers with a referral code, their tarifas and promos are now copied from the referring user. Also refactored Usuario_promo and Usuario_tarifa models to use fillable attributes and improved method formatting. Added Swiper CSS/JS to app layout.

app/Models/Usuario_promo.php

@@ -9,7 +9,7 @@ class Usuario_promo extends Model
 {
     use HasFactory;
 
-    protected $hidden = [
+    protected $fillable = [
         'usuario_id',
         'promocion_id',
         'precio',
@@ -17,12 +17,12 @@ class Usuario_promo extends Model
         'visible',
     ];
 
-    public function  usuario()
+    public function usuario()
     {
         return $this->belongsTo(User::class, 'usuario_id');
     }
 
-    public function  promocion()
+    public function promocion()
     {
         return $this->belongsTo(Promociones::class, 'promocion_id');
     }

app/Models/Usuario_tarifa.php

@@ -16,11 +16,13 @@ class Usuario_tarifa extends Model
         'visible',
     ];
 
-    public function  usuario(){
-        return $this ->belongsTo(User::class,'usuario_id');
+    public function usuario()
+    {
+        return $this->belongsTo(User::class, 'usuario_id');
     }
 
-    public function  tarifa(){
-        return $this ->belongsTo(Tarifas::class,'tarifa_id');
+    public function tarifa()
+    {
+        return $this->belongsTo(Tarifas::class, 'tarifa_id');
     }
 }