Transfer calendar owner via UI

Is your feature request related to a problem? Please describe.

When users are leaving the organisation or project or change to a different department, they often own important calendars they have shared with their respective people groups/colleagues.

A common frustration of these users is, that they cannot transfer the ownership of their own calendars to someone else, without involving an administrator every time.

Describe the solution you'd like

Include a transfer owner dialog in the share dialog / details of each calendar you own.
Show the current owner of the calendar, if you're looking at a calendar that was shared with you.

Describe alternatives you've considered

The occ command for migrating calendars is simply not an option - the users need to be able to do basic self-service here.

Exporting and then importing a calendar is not an option either - already attached metadata gets lost and shares would have to be reconfigured.

• this would be way too complicated for most users.

Additional context

No response

Start by tracing the calendar share dialog and calendar details UI, then inspect how ownership and sharing permissions are currently handled. Done means an owner can transfer a calendar through the UI, shared calendars show their current owner, and existing metadata and shares remain intact.