feat: add booking time ranges and repeating series

assets/controllers/bookingform_controller.js

@@ -0,0 +1,25 @@
+import { Controller } from '@hotwired/stimulus';
+
+/*
+ * Shows and hides the parts of the booking form that only apply in some states: the time fields
+ * when "ganzer Tag" is off, the recurrence fields when a repetition is picked, and the weekday
+ * boxes only for a weekly rule.
+ *
+ * Purely client-side, so it is Stimulus rather than an htmx form refresh -- there is nothing the
+ * server needs to decide here. The server still validates every one of these rules, because a
+ * hidden field is not an absent one.
+ */
+export default class extends Controller {
+    static targets = ['times', 'repeat', 'weekdays'];
+
+    toggleTimes(event) {
+        this.timesTarget.classList.toggle('hidden', event.target.checked);
+    }
+
+    toggleRepeat(event) {
+        const rule = event.target.value;
+
+        this.repeatTarget.classList.toggle('hidden', rule === '');
+        this.weekdaysTarget.classList.toggle('hidden', rule !== 'weekly');
+    }
+}