fix: add explicit type annotations for parse and remove unused imports

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

src/modes/diff.rs

@@ -1,4 +1,4 @@
-use anyhow::{anyhow, Context, Result};
+use anyhow::{Context, Result};
 use clap::Command;
 use std::io::Read;
 use std::os::fd::FromRawFd;
@@ -146,7 +146,7 @@ fn write_item_to_pipe(
     compression_type: crate::compression_engine::CompressionType,
     pipe_writer_raw: std::fs::File,
 ) -> Result<(), anyhow::Error> {
-    use std::io::{BufWriter, BufReader};
+    use std::io::BufWriter;
     
     let mut buffered_pipe_writer = BufWriter::new(pipe_writer_raw);
     
@@ -305,8 +305,8 @@ pub fn mode_diff(
     let (item_path_a, item_path_b) = setup_diff_paths_and_compression(&item_service, &item_a, &item_b)?;
     
     // Get compression types from the items
-    let compression_type_a = item_a.item.compression.parse()?;
-    let compression_type_b = item_b.item.compression.parse()?;
+    let compression_type_a: crate::compression_engine::CompressionType = item_a.item.compression.parse()?;
+    let compression_type_b: crate::compression_engine::CompressionType = item_b.item.compression.parse()?;
 
     let ((fd_a_read, fd_a_write), (fd_b_read, fd_b_write)) = setup_diff_pipes()?;
     let (_fd_a_read_guard, _fd_b_read_guard) = setup_fd_guards(fd_a_read, fd_b_read);