Add a switch to make search case sensitive (a bonus: regex searches)

Find in page has a toggle for case sensitive search and I think that searching in mail is more akin to that than other searches in panels. It would come quite handy sometimes when I am looking for a particular mail and am getting too much results. (One example is to look for bugs sent to Vivaldi, I would just look for VB- and it would show them, now it also for some reason displays a lot of false positives. I’m aware I can also search for [jira], it is just an example).

Actually, I would not mind being able to have case sensitive search in the panels too, probably through a menu, where there already are settings for panels.

A bonus feature would be regular expression search for mail (this would need to be toggable), which is basically an extension of this feature request for find in page:
forum.vivaldi.net/topic/24116/regex-support-for-find-in-page

Also relevant is this thread: forum.vivaldi.net/topic/62636/wildcards-boolean-regexp-in-searches-and-filters which I think is more of a bug report and might have been fixed in the meantime – I remember filters were a bit broken and mail search was definitely quite broken for a time.