show only busy active for shared edits

Steps to reproduce

1. share a calendar with edit rights to a user
2. with that user add a event, choose "When shared show only busy"
3. the user does not see the description any more, title changes to "busy"
4. switch back to "show full event", title and description is lost

Expected behavior

For a user with write permission, the option "When shared show only busy" should have no visible effect. Only puplic views should be restricted.

Actual behavior

• For a user with write permission, after switching to "When shared show only busy", title switches to busy, description is not shown
• After switching back to "show full event" description is lost, title is changed to "busy"

Calendar app version

5.3.5

CalDAV-clients used

No response

Browser

Firefox

Client operating system

No response

Server operating system

No response

Web server

None

Database engine version

None

PHP engine version

None

Nextcloud version

31.0.6

Updated from an older installed version or fresh install

Updated from an older version

List of activated apps

Nextcloud configuration

Web server error log

Log file

Browser log

Additional info

No response

Start by reproducing the shared-calendar edit-permission flow described in the issue: switch an event to “When shared show only busy,” then restore “show full event.” Trace the calendar sharing and event update entry points to find where write-permitted users are restricted or event fields are overwritten. Done means editors retain the title and description while only public views remain limited.