integrate history `-c` with `--nextep-countdown`

[port19x]

Is your feature request related to a problem? Please describe.
not really

Describe the solution you'd like
When watching an ongoing show via -c, it doesn't show up again unless there is a new episode.
Instead, keep it selectable, running it through the nextep countdown if selected.

Describe alternatives you've considered
We can also just not. It will probably be complicated to implement

Additional context
Occurred to me in todays testing

[sghoshm]

Hey, I ended up implementing this based on your suggestion.

It keeps ongoing anime selectable in -c, and if there’s no new episode, it triggers the nextep countdown instead of attempting playback.

PR: #1705

Would love your feedback!