feat: add two- and four-weekly series and drop the weekday picker

assets/controllers/bookingform_controller.js

@@ -2,24 +2,21 @@ 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.
+ * when "ganzer Tag" is off, and the recurrence fields when a repetition is picked. The weekday a
+ * series runs on is derived from its start date, so there is nothing to toggle for it.
  *
  * 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'];
+    static targets = ['times', 'repeat'];
 
     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');
+        this.repeatTarget.classList.toggle('hidden', event.target.value === '');
     }
 }