Squashed commit of the following:

commit 1dc4e29c69
Author: ncoronel <ncoronel@quo.ar>
Date:   Wed Aug 19 13:58:03 2026 -0300

    refactor(reservations): unify expiration command

commit 093e894cc3
Author: ncoronel <ncoronel@quo.ar>
Date:   Wed Aug 19 13:48:09 2026 -0300

    feat(cart): expire abandoned stock reservations

commit fdf0f3328f
Author: ncoronel <ncoronel@quo.ar>
Date:   Wed Aug 19 12:53:12 2026 -0300

    refactor(stock): implement expiration for stock reservations and add configuration

commit 8d6bcdcc43
Author: ncoronel <ncoronel@quo.ar>
Date:   Wed Aug 19 12:38:21 2026 -0300

    refactor(cart): invalidate payment on actual changes

commit 3206e293eb
Author: ncoronel <ncoronel@quo.ar>
Date:   Wed Aug 19 12:24:48 2026 -0300

    refactor(cart): own checkout item editing

commit aed99bd05e
Author: ncoronel <ncoronel@quo.ar>
Date:   Wed Aug 19 12:14:57 2026 -0300

    refactor(checkout): remove legacy purchase item reservations

commit f1649e0e4b
Author: ncoronel <ncoronel@quo.ar>
Date:   Wed Aug 19 12:06:29 2026 -0300

    refactor(checkout): materialize purchase items on confirmation

commit e6c4b40a37
Author: ncoronel <ncoronel@quo.ar>
Date:   Wed Aug 19 12:06:19 2026 -0300

    feat(inventory): add traceable cart stock reservations

app/Domains/Cart/Services/GuestCartMergeService.php

@@ -34,6 +34,10 @@ class GuestCartMergeService
                 ->first();
 
             if ($userCart !== null) {
+                $userCart->items()
+                    ->orderBy('id')
+                    ->pluck('id')
+                    ->each(fn (int $itemId) => $userCart->removeItem($itemId));
                 $userCart->update([
                     'status' => 'converted',
                 ]);