Fix delivery deletion: allow negative stock instead of clamping to 0

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

app/Filament/User/Resources/SpiceSupplierResource/Pages/EditSpiceSupplier.php

@@ -21,9 +21,7 @@ class EditSpiceSupplier extends EditRecord
                 )
                 ->before(function ($record) {
                     if ($record->spice) {
-                        $record->spice->update([
-                            'quantity' => max(0, $record->spice->quantity - $record->amount),
-                        ]);
+                        $record->spice->decrement('quantity', $record->amount);
                     }
                 }),
         ];