Feature: Implement Feed

[Giszmo]

Implement the feed tab. It should show events authored by the in-group, with context. Like Twitter, the context should not branch out but initially show only the most relevant author's events, indicating when there are more replies from the in-group with a reply counter.

[Giszmo]

This depends on #13

[Giszmo]

All accounts should be marked with the degree at which they are followed. Users should immediately see the difference between a direct follow and a 4th degree follow or an out-group account. If your follows reply to an out-group note, that note should be shown as part of the thread that made it into the user's feed.

Replies to in-group notes should only be shown if in-group accounts replied (referenced) them with any of their events. Therefore we should never need to query nostr for "#e":[<eventId>] like other clients do. I suspect they will quickly get mostly spam that way.

I don't care about how many out-group profiles liked or replied to an event. It's so gameable, it's just irrelevant.

[Giszmo]

The feed already is shown but it loads too slowly and all at once. Get most recent first.