fix: resolve PIPESIZE redefinition and unused variable warnings

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

src/common/mod.rs

@@ -3,6 +3,3 @@ pub mod status;
 
 /// Standard buffer size for I/O operations (8KB)
 pub const PIPESIZE: usize = 8192;
-
-// Re-export for easy access
-pub use self::PIPESIZE;

src/services/async_item_service.rs

@@ -26,8 +26,8 @@ impl AsyncItemService {
     }
 
     pub async fn get_item(&self, id: i64) -> Result<ItemWithMeta, CoreError> {
-        let db = self.db.clone();
-        let item_service = self.item_service.clone();
+        let _db = self.db.clone();
+        let _item_service = self.item_service.clone();
 
         tokio::task::spawn_blocking(move || {
             let conn = db.blocking_lock();
@@ -193,7 +193,6 @@ impl AsyncItemService {
         
         // Convert the reader into an async stream manually
         // Since ReaderStream requires AsyncRead, we'll create our own implementation
-        use tokio_stream::StreamExt;
         use tokio_util::bytes::Bytes;
         
         // Create a channel to stream data between the blocking thread and async runtime