Taking a screenshot at anytime during recording

[sassman]

While I'm recording I want to make a static screenshot with a keystroke.

• This screenshot should follow the -o argument with a suffix like _screenshot-<timestamp> and be stored in ./ as the other files
• The keystroke should be not interfering with the command or terminal, like F2 or CTRL-ALT-CMD-S or so
• the filters/decorations/wallpaper should be applied for this screenshot too
• it should be mentioned in the summary, eg. taken at 31sec -> t-rec_screenshot-20251211-010122.tga
• the image output format should be tga or png (maybe default png) and a cli argument should control it e.g. --screenshot-format tga