fix: remove generic type from ApiResponse in delete item endpoint documentation

Co-authored-by: aider (openai/andrew/openrouter/qwen/qwen3-coder) <aider@aider.chat>

src/modes/server/api/item.rs

@@ -163,7 +163,7 @@ pub async fn handle_post_item(
     delete,
     path = "/api/item/{item_id}",
     responses(
-        (status = 200, description = "Successfully deleted item", body = ApiResponse<()>),
+        (status = 200, description = "Successfully deleted item", body = ApiResponse),
         (status = 401, description = "Unauthorized"),
         (status = 404, description = "Item not found"),
         (status = 500, description = "Internal server error")