refactor(application): fix 4 code smells — validate username input, extract ownership guard and dedup helpers

crates/application/src/services/federation_event.rs

@@ -2,8 +2,9 @@ use std::sync::Arc;
 use domain::{
     errors::DomainError,
     events::DomainEvent,
-    models::thought::Visibility,
+    models::thought::{Thought, Visibility},
     ports::{OutboundFederationPort, ThoughtRepository, UserRepository},
+    value_objects::ThoughtId,
 };
 
 pub struct FederationEventService {
@@ -14,6 +15,12 @@ pub struct FederationEventService {
 }
 
 impl FederationEventService {
+    fn object_ap_id(&self, thought: &Thought, thought_id: &ThoughtId) -> String {
+        thought.ap_id.clone().unwrap_or_else(|| {
+            format!("{}/thoughts/{}", self.base_url, thought_id)
+        })
+    }
+
     pub async fn process(&self, event: &DomainEvent) -> Result<(), DomainError> {
         match event {
             DomainEvent::ThoughtCreated { thought_id, user_id, .. } => {
@@ -52,9 +59,7 @@ impl FederationEventService {
                     Some(t) => t,
                     None => return Ok(()),
                 };
-                let object_ap_id = thought.ap_id.clone().unwrap_or_else(|| {
-                    format!("{}/thoughts/{}", self.base_url, thought_id)
-                });
+                let object_ap_id = self.object_ap_id(&thought, thought_id);
                 self.ap.broadcast_announce(user_id, &object_ap_id).await
             }
 
@@ -63,9 +68,7 @@ impl FederationEventService {
                     Some(t) => t,
                     None => return Ok(()),
                 };
-                let object_ap_id = thought.ap_id.clone().unwrap_or_else(|| {
-                    format!("{}/thoughts/{}", self.base_url, thought_id)
-                });
+                let object_ap_id = self.object_ap_id(&thought, thought_id);
                 self.ap.broadcast_undo_announce(user_id, &object_ap_id).await
             }