A community announces back to its author's own server

Lemmy keeps its user's post in a community pending until the community announces it back. A community hosted here
announced only to its followers, so a post from a server where nobody follows the community stayed pending there; the
author's own server (its shared inbox) now gets the announces too. INTEROP records, confirmed live, why Lemmy refuses
our Flags (an Application reporter, no `to`, an array object). FEDERATION.md's custom emoji line is put back before the
replies paragraph.

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

docs/INTEROP.md

@@ -503,7 +503,9 @@ on a Page: pins live in `featured`, locks in `Lock`.
 - **Anti-spam:** activities for a community are accepted only if a local user follows it.
 - **Actors:** a Create, vote, moderation action or Flag must come from a Person, Service or Organization. **A Group or
   Application actor fails to parse**, so moderation comes from the moderator Person. Our Flags, sent by an
-  Application instance actor, probably fail *(unconfirmed)*.
+  Application instance actor with no `to` and an array `object` (the account and the post), are refused: confirmed live
+  2026-10-06, Lemmy 1.0.0-beta.2 answers 400 and keeps no report. Reaching its moderators needs an anonymous
+  `Service`-typed reporter, `to: [the post's community]` and the post alone as `object`.
 - **Flags:** exactly one `to` (community or site); `object` a URL or an array; the reason in `summary` or `content`.
 - **Moderation trust:** an action is trusted when it is on the community's or the object's host (FEP-fe34), or when its
   actor is in the moderators list Lemmy fetched.

docs/ROADMAP.md

@@ -661,7 +661,8 @@ it, raw where it doesn't.
     ban of a persona refuses its posts there and shows as `blocked_by`), featured, moderators, `Warn`, `Resolve`;
   - votes in and out; link posts; flairs; `Feed` actors; community polls; post `Move`;
   - the outbound shape Lemmy requires;
-  - communities we host announce to the author's own instance too;
+  - communities we host announce to the author's own instance too: **done 2026-10-06** (its server's shared inbox,
+    whether anyone there follows the community or not: Lemmy keeps its user's post pending until it is announced back);
   - Flags from a `Service`-typed reporter actor.
 - **GoToSocial interaction policies** (**done 2026-10-05**, `InteractionApprovals`): stored and shown as
   `interaction_policy`; `ReplyRequest`/`LikeRequest`/`AnnounceRequest` where approval is needed; `Accept{result}`