Resizing a task on the calendar does not save when reloading the page.

Steps to reproduce

• Try to re-size a task on the calendar
• Refresh the page

Expected behavior

• It saves

Actual behavior

• It does not save the length of the task (it can only do 30 minute blocks)

Additional info

When adding a new task on the calendar, you can't specify a length.

Since tasks already have (and use) the "start_date" field, the solution would be to use "due_date" and use those to calculate the length in the calendar app.

Currently it uses "due_date" to show the start on the calendar, which doesn't really make sense at all, it should start at "start_date" and end at "due_date".

I would consider this a bug since moving the task length appears to work, but just does not save and re-sets on page reload.

This would allow us to create tasks and manage them between tasks and calendar more efficiently.

There are many requests for this to be fixed on the tasks repo (https://github.com/nextcloud/tasks/issues/2563) but it is a calendar issue.

Start by tracing task resizing and persistence in the Nextcloud Calendar app, using the calendar task editor and its handling of start_date and due_date as entry points. Confirm that a resized task reloads with the same start and end times, and that creating a task supports its intended length.