ssb: The unread line can be used to make everything above read.

apps/ssb/tf-tab-news-feed.js

@@ -486,6 +486,7 @@ class TfTabNewsFeedElement extends LitElement {
 				channel=${this.channel()}
 				channel_unread=${this.channels_unread?.[this.channel()]}
 				.recent_reactions=${this.recent_reactions}
+				@mark_all_read=${this.mark_all_read}
 			></tf-news>
 			${more}
 		`);