khal: Set default calendar

Otherwise grocy, a read-only calendar, is the default.

users/simon/modules/vdirsyncer.nix

@@ -3,6 +3,7 @@ let
   contactsBasePath = "${config.xdg.dataHome}/contacts";
   calendarBasePath = "${config.xdg.dataHome}/calendar";
 
+  personalCalendarUuid = "bda1b0cb-994c-366c-e1fe-de646c26e337";
   personalContactsUuid = "d6abd3ea-3abd-7550-9f24-f06293d36a82";
 
   fetchCommand = command:
@@ -104,6 +105,9 @@ in
       ]);
 
     "khal/config".text = /* toml */ ''
+      [default]
+      default_calendar = ${personalCalendarUuid}
+
       [calendars]
 
       [[calendar_personal]]