[Feature Request] Ability to change a state of a subscription in a calendar to "paid" or others

[anthuav]

Hi, first of all, I really appreciate Wallos it’s been a great tool for keeping track of my invoices, like electricity and gas bills. One small feature that would make it even more helpful is the ability to mark invoices in the calendar as 'paid.' Maybe changing the border or header color would work? For example, GREEN for paid and RED for unpaid. It would also be great if users could customize these colors in settings. Thanks for considering this!