Allow swiping to read/unread entries in per-feed view

[emersion]

Checklist

• I checked, but didn't find any duplicates (open OR closed) of this issue in the repo.
• This issue contains only one feature request. I will open one issue for every feature I want to request.

What feature do you want?

1. Go to the "Feeds" tab
2. Tap on a feed
3. Try swiping an entry, it doesn't work

Why do you want this feature?

The combined list ("News" tab) is often crowded by chatty feeds, so the per-feed view is useful to check less chatty feeds. Some entries may not be of interest, so marking them as read without opening them is handy.