fix: AP bugs — backfill mapping, review activity type, also_known_as parse

- BackfillRequested now maps to BackfillFollower domain event (not FollowAccepted);
  worker calls run_backfill_for_follower to send LOCAL content to new follower inbox,
  instead of incorrectly trying to import from an inbox URL as if it were an outbox
- reviews broadcast as Create activity instead of Add (semantically correct)
- also_known_as JSON parse failure logs warning + preserves raw string as single-element
  vec instead of silently returning empty

crates/adapters/activitypub/src/event_handler.rs

@@ -123,7 +123,7 @@ impl ActivityPubEventHandler {
         let json = serde_json::to_value(obj)?;
 
         self.ap_service
-            .broadcast_add_to_followers(user_id.value(), ap_id, json)
+            .broadcast_create_note(user_id.value(), json, ApVisibility::Public, vec![])
             .await?;
 
         Ok(())

crates/adapters/activitypub/src/federation_event_bridge.rs

@@ -22,16 +22,10 @@ impl k_ap::EventPublisher for FederationEventBridge {
                 owner_user_id,
                 follower_inbox_url,
             } => {
-                tracing::info!(
-                    owner = %owner_user_id,
-                    inbox = %follower_inbox_url,
-                    "federation BackfillRequested → FollowAccepted"
-                );
                 self.domain_publisher
-                    .publish(&DomainEvent::FollowAccepted {
-                        local_user_id: UserId::from_uuid(owner_user_id),
-                        remote_actor_url: follower_inbox_url.clone(),
-                        outbox_url: follower_inbox_url,
+                    .publish(&DomainEvent::BackfillFollower {
+                        owner_user_id: UserId::from_uuid(owner_user_id),
+                        follower_inbox_url,
                     })
                     .await
                     .map_err(|e| anyhow::anyhow!(e.to_string()))

crates/adapters/activitypub/src/port.rs

@@ -34,6 +34,7 @@ pub trait ActivityPubPort: Send + Sync {
     async fn import_remote_outbox(&self, outbox_url: &str, actor_url: &str) -> anyhow::Result<()>;
     async fn followers_collection_json(&self, user_id: Uuid, page: Option<u32>) -> anyhow::Result<String>;
     async fn following_collection_json(&self, user_id: Uuid, page: Option<u32>) -> anyhow::Result<String>;
+    async fn run_backfill_for_follower(&self, owner_user_id: Uuid, follower_inbox_url: String) -> anyhow::Result<()>;
 }
 
 #[async_trait]
@@ -109,6 +110,9 @@ impl ActivityPubPort for ActivityPubService {
     async fn following_collection_json(&self, user_id: Uuid, page: Option<u32>) -> anyhow::Result<String> {
         self.following_collection_json(user_id, page).await
     }
+    async fn run_backfill_for_follower(&self, owner_user_id: Uuid, follower_inbox_url: String) -> anyhow::Result<()> {
+        self.run_backfill_for_follower(owner_user_id, follower_inbox_url).await
+    }
 }
 
 pub struct NoopActivityPubService;
@@ -175,4 +179,7 @@ impl ActivityPubPort for NoopActivityPubService {
     async fn following_collection_json(&self, _: Uuid, _: Option<u32>) -> anyhow::Result<String> {
         Ok(String::new())
     }
+    async fn run_backfill_for_follower(&self, _: Uuid, _: String) -> anyhow::Result<()> {
+        Ok(())
+    }
 }