Add sticky month headers in Event List view

[Farijo]

Checklist

• I made sure that there are no existing issues - open or closed - to which I could contribute my information.
• I made sure that there are no existing discussions - open or closed - to which I could contribute my information.
• I have read the FAQs inside the app (Menu -> About -> FAQs) and my problem isn't listed.
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• This issue contains only one feature request.
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Feature description

Currently, in the Event List view, the month and year are displayed as a simple separator between events. When scrolling through a long list of events (especially when many events occur in the same month), it is easy to lose track of which month is currently being viewed.

I suggest implementing sticky headers for the month separators. As the user scrolls down the list, the current month header should "stick" to the top of the screen (just below the app bar) until it is pushed away by the next month's header.

Why do you want this feature?

• Improved Orientation: Users can immediately see the current month and year without having to scroll back up to the last separator.
• Better UX: This is a standard behavior in many modern calendar and gallery apps which makes navigating long lists much more intuitive.
• Visual Consistency: It aligns the Event List view with the "scrolling" nature of the application, providing a more polished and professional feel.

Additional information

• This should ideally be applied to the main event list view and the widget event list.
• The sticky title could also includes the year. Either all the time or when the list changes from year to year.
• Optional: A toggle in the "Display" settings could allow users to enable/disable this behavior if they prefer the classic static separators.