Currently, videos are marked as watched as soon as playback is started. If one decides to pause a video and continue watching it later, it has vanished from the subscription feed.

I would like to have the ability to configure a certain time when a video is marked as watched (preferably a configurable value like "mark as watched after __%").

I realise this probably requires JS to implement. It could therefore be opt-in (e.g. a checkbox "mark as watched immediately" that must be disabled).

Somewhat related to #1713. This has been brought up before in #607.