feat: relay dm_close and dm_reopen to federated peers

Queue dm_close relay in DELETE /api/dm/:id after broadcasting locally,
and queue dm_reopen relay inside the myDm.closed === 1 branch of POST
/api/dm so peers are notified only on actual reopen, not new DM creation.

packages/server/src/routes/dm.ts

@@ -26,6 +26,7 @@ import {
   appendMutationLog,
   queueOutboxEvent,
   queueDmRelay,
+  queueDmCloseRelay,
   getDmParticipants,
   getGroupDmTargetOrigins,
   isFederationRelayEnabled,
@@ -445,6 +446,9 @@ export async function dmRoutes(app: FastifyInstance): Promise<void> {
               eq(schema.dmMembers.userId, request.userId),
             ))
             .run();
+
+          // Relay reopen to federated peers
+          queueDmCloseRelay(myDm.dmChannelId, request.userId, 'dm_reopen');
         }
 
         const dmMemberRows = db.select()
@@ -854,6 +858,9 @@ export async function dmRoutes(app: FastifyInstance): Promise<void> {
       dmChannelId: id,
     });
 
+    // Relay close to federated peers
+    queueDmCloseRelay(id, request.userId, 'dm_close');
+
     return reply.code(200).send({ success: true });
   });