A community's vote on our reply counts, followed or not

Lemmy sends a vote to the community alone, which relays it to the post's
server. A persona's reply in a thread of a community nobody here follows
lost its Lemmy upvotes: the relay was dropped as "not followed". Such a
relay is now taken when the vote (or its undo) is on one of our posts in a
thread rooted in that community; from any other unfollowed group it is
still dropped. For that, a post keeps the community its `audience` names
(FEP-1b12) however it arrived, fetched for a thread as well as announced.

Found by the town's village (p191: 1 like counted of 2).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01LsXgEaXee4GCU1hwYgPJXw

PrivaPub/Federation/Inbox/RemotePosts.cs

@@ -94,6 +94,11 @@ namespace PrivaPub.Federation.Inbox
 				Cc = cc.ToList(),
 				Url = note.Url,
 				ContextURI = note.Context,
+				// the community it lives in (FEP-1b12), as the post itself names it: a post fetched for a thread knows its
+				// community as well as one its community announced
+				AudienceURI = note.Audience != default && note.Audience != author.ActorURI && !note.Audience.EndsWith("/followers", StringComparison.Ordinal)
+					? note.Audience
+					: default,
 				QuoteURI = note.QuoteUri,
 				ObjectType = note.Type,
 				Title = note.Title,