feat: replace hardcoded buffer sizes with PIPESIZE constant

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

src/services/async_item_service.rs

@@ -1,3 +1,4 @@
+use crate::common::PIPESIZE;
 use crate::services::error::CoreError;
 use crate::services::item_service::ItemService;
 use crate::services::types::{ItemWithContent, ItemWithMeta};
@@ -204,7 +205,7 @@ impl AsyncItemService {
             // Apply offset by reading and discarding bytes
             if offset > 0 {
                 let mut remaining = offset;
-                let mut buf = [0; 8192];
+                let mut buf = [0; PIPESIZE];
                 while remaining > 0 {
                     let to_read = std::cmp::min(remaining, buf.len() as u64);
                     match reader.read(&mut buf[..to_read as usize]) {
@@ -220,7 +221,7 @@ impl AsyncItemService {
             
             // Read and send data up to the specified length
             let mut remaining_length = length;
-            let mut buffer = [0; 8192];
+            let mut buffer = [0; PIPESIZE];
             
             loop {
                 // Determine how much to read in this iteration