Feature Request: User-specific notification preferences per shared calendar

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

Background

This idea was originally discussed in event_update_notification#154

It became clear that implementing this in the event_update_notification app is not ideal, since the app is backend-only and does not provide UI integration with the Calendar app.

Instead, it was suggested that the feature should be implemented directly in the Calendar app.

Problem

Currently, users receive notifications about updates in shared calendars without being able to control which specific calendars trigger those notifications.
For users with access to many shared calendars, this can quickly lead to notification overload, even if they only want to be informed about changes in a few selected calendars.

Proposed Solution

Each user should be able to decide individually for which shared calendars they want to receive event update notifications.

Possible implementations:

1. Calendar settings option

• In the properties of each calendar (next to color, visibility, etc.), add a toggle: “Enable update notifications for this calendar”.

2. Global user settings

• In the personal settings, show a list of all shared calendars available to the user.
• For each calendar, allow enabling or disabling notifications.

Alternatives considered

• Keeping the current global notification system (status quo) → does not solve the issue of selective notifications.
• Letting only the calendar owner configure notifications → takes away individual user control.

Benefits

• Improved focus and less noise for users.
• Especially valuable for users collaborating across multiple teams, groups, or communities.
• Flexible, since each user can tailor notifications to their own needs.

Start by reviewing the Calendar app's existing calendar properties, personal settings, and event update notification integration. Decide whether per-calendar controls belong in calendar properties or global user settings, then define how each user's choices affect notifications for shared calendars. Done means users can independently enable or disable update notifications for each shared calendar.