Automatically remember reading position in long feeds

Description:
When reading a very long feed, it would be helpful if the app could automatically remember the current reading position (scroll position).
That way, when coming back to the same feed later, the user can resume reading exactly where they left off — without having to manually scroll again.

Why?

• Improves the reading experience for long or dense feeds.
• Saves time when resuming reading after closing or switching feeds.
• Especially useful for users who read across multiple sessions or on mobile devices.

Possible implementation:

• Automatically save the last scroll position for each feed.
• Restore it when reopening that feed.

Optionally, add a setting to enable/disable this behavior.

The issue names no files, tests, or entry points. Start by locating the long-feed screen and its feed-specific scroll state, then clarify persistence scope and whether the optional setting is required. Done means reopening each feed restores its prior position without disrupting normal navigation.