fix: resync room selections with travel data before step 2

src/Model/RoomSelectionAdjustment.php

@@ -0,0 +1,30 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Model;
+
+/**
+ * A room selection the current travel data no longer supports in full.
+ *
+ * A room that disappeared altogether is the same case with nothing left to book, so it is reported
+ * as an adjustment down to zero rather than as a second kind of result.
+ */
+final readonly class RoomSelectionAdjustment
+{
+    public function __construct(
+        public int $roomId,
+        public ?string $label,
+        public int $requestedQuantity,
+        public int $bookableQuantity,
+    ) {
+    }
+
+    /**
+     * Whether the room is gone entirely rather than merely reduced.
+     */
+    public function isDropped(): bool
+    {
+        return 0 === $this->bookableQuantity;
+    }
+}