refactor: Improve error handling and borrowing in item services

Co-authored-by: aider (openai/andrew/openrouter/deepseek/deepseek-chat-v3.1) <aider@aider.chat>

src/services/async_item_service.rs

@@ -54,7 +54,7 @@ impl AsyncItemService {
             f(&conn, &item_service)
         })
         .await
-        .unwrap()
+        .map_err(|e| CoreError::Other(anyhow::anyhow!("Blocking task failed: {}", e)))?
     }
 
     pub async fn get_item(&self, id: i64) -> Result<ItemWithMeta, CoreError> {
@@ -186,7 +186,7 @@ impl AsyncItemService {
                 ).map(|(reader, _, _)| reader)
             })
             .await
-            .unwrap()?
+            .map_err(|e| CoreError::Other(anyhow::anyhow!("Blocking task failed: {}", e)))?
         };
 
         // Convert the reader into an async stream manually