Fix code quality: trailing whitespace, unused imports, clippy warnings

- Fix trailing whitespace in kex.rs and s3.rs
- Add missing KexProposal import in kex_complete.rs
- Auto-fix clippy warnings across all crates
- All 153 tests pass

markbase-core/src/rsync/checksum.rs

@@ -1,4 +1,3 @@
-use anyhow::Result;
 use md5::compute;
 
 pub struct RollingChecksum {

markbase-core/src/rsync/compress.rs

@@ -50,6 +50,12 @@ pub struct DecompressionStream {
     decompressor: Decompress,
 }
 
+impl Default for DecompressionStream {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
 impl DecompressionStream {
     pub fn new() -> Self {
         Self {

markbase-core/src/rsync/handler.rs

@@ -1,7 +1,5 @@
-use crate::rsync::checksum::{compute_block_checksums, BlockChecksum};
-use crate::rsync::compress::{CompressionStream, DecompressionStream};
 use crate::rsync::delta::{DeltaAlgorithm, DeltaInstruction};
-use crate::rsync::protocol::{RsyncCommand, RsyncProtocol};
+use crate::rsync::protocol::RsyncCommand;
 use crate::rsync::RsyncConfig;
 use anyhow::Result;
 use std::sync::Arc;

markbase-core/src/rsync/protocol.rs

@@ -162,6 +162,12 @@ pub struct RsyncHandshake {
     negotiated_version: u32,
 }
 
+impl Default for RsyncHandshake {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
 impl RsyncHandshake {
     pub fn new() -> Self {
         Self {