feat(ap): broadcast Update(Actor) when user updates their profile

crates/domain/src/events.rs

@@ -60,6 +60,9 @@ pub enum DomainEvent {
     UserRegistered {
         user_id: UserId,
     },
+    ProfileUpdated {
+        user_id: UserId,
+    },
     FetchRemoteActorPosts {
         actor_ap_url: String,
         outbox_url: String,

crates/domain/src/ports.rs

@@ -471,4 +471,7 @@ pub trait OutboundFederationPort: Send + Sync {
         object_ap_id: &str,
         author_inbox_url: &str,
     ) -> Result<(), DomainError>;
+
+    /// Fan out an Update(Actor) to all accepted followers after a profile change.
+    async fn broadcast_actor_update(&self, user_id: &UserId) -> Result<(), DomainError>;
 }