fix: correct unread notification marking logic

[LangLangBart]

description

• fix CTRL-A should mark only filtered notifications that you see, not all-at-all #89

Allow the user to filter the list and only mark notifications as read for the filtered list with ctrl-a.
Also enable --multi selection to allow the user to select multiple entries and mark them as read with ctrl-t.

[LangLangBart]

Since the ⇥ Tab key is by default used for toggling the preview, one would need to alter the existing key binding or define a custom binding, e.g. ⌃ Control + Y

[sitano]

works! 🙌