fix: content negotiation for followers/following — resolve AP router conflict

crates/domain/src/ports.rs

@@ -199,6 +199,16 @@ pub trait FederationActionPort: Send + Sync {
     async fn lookup_actor(&self, handle: &str) -> Result<RemoteActor, DomainError>;
     async fn follow_remote(&self, local_user_id: &UserId, handle: &str) -> Result<(), DomainError>;
     async fn actor_json(&self, user_id: &UserId) -> Result<String, DomainError>;
+    async fn followers_collection_json(
+        &self,
+        user_id: &UserId,
+        page: Option<u32>,
+    ) -> Result<String, DomainError>;
+    async fn following_collection_json(
+        &self,
+        user_id: &UserId,
+        page: Option<u32>,
+    ) -> Result<String, DomainError>;
 }
 
 #[async_trait]