feat: groups price calculator admin crud, booking/offer flow and api

src/Model/CalendarMonth.php

@@ -0,0 +1,18 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Model;
+
+final readonly class CalendarMonth
+{
+    /**
+     * @param array<int, CalendarDay> $days keyed by day-of-month number
+     */
+    public function __construct(
+        public string $label,
+        public int $firstDow,
+        public array $days,
+    ) {
+    }
+}