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/download/storage.rs

@@ -1,5 +1,5 @@
 use serde::{Deserialize, Serialize};
-use std::path::{Path, PathBuf};
+use std::path::Path;
 
 #[derive(Debug, Clone, Serialize, Deserialize)]
 pub struct FileInfo {
@@ -23,17 +23,17 @@ pub struct FileListResponse {
 pub fn scan_uploaded_files(user_id: &str) -> FileListResponse {
     let base_path = format!("/Users/accusys/Downloads/{}", user_id);
     let path = Path::new(&base_path);
-    
+
     let mut files = Vec::new();
     let mut total_size = 0u64;
-    
+
     if path.exists() {
         scan_directory_recursive(path, path, &mut files, &mut total_size);
     }
-    
+
     FileListResponse {
         user_id: user_id.to_string(),
-        base_path: base_path,
+        base_path,
         total_files: files.len(),
         total_size,
         files,
@@ -49,24 +49,25 @@ fn scan_directory_recursive(
     if let Ok(entries) = std::fs::read_dir(current) {
         for entry in entries.flatten() {
             let path = entry.path();
-            
+
             if path.is_file() {
-                let filename = path.file_name()
+                let filename = path
+                    .file_name()
                     .and_then(|n| n.to_str())
                     .unwrap_or("unknown")
                     .to_string();
-                
-                let file_size = entry.metadata()
-                    .map(|m| m.len())
-                    .unwrap_or(0);
-                
-                let relative_path = path.strip_prefix(base)
+
+                let file_size = entry.metadata().map(|m| m.len()).unwrap_or(0);
+
+                let relative_path = path
+                    .strip_prefix(base)
                     .ok()
                     .and_then(|p| p.to_str())
                     .map(|s| s.to_string())
                     .unwrap_or_else(|| filename.clone());
-                
-                let upload_time = entry.metadata()
+
+                let upload_time = entry
+                    .metadata()
                     .ok()
                     .and_then(|m| m.modified().ok())
                     .and_then(|t| {
@@ -75,13 +76,16 @@ fn scan_directory_recursive(
                             .map(|dt| dt.format("%Y-%m-%dT%H:%M:%SZ").to_string())
                     })
                     .unwrap_or_else(|| chrono::Utc::now().format("%Y-%m-%dT%H:%M:%SZ").to_string());
-                
+
                 let file_hash = if file_size > 0 {
                     compute_file_hash(&path).ok()
                 } else {
-                    Some("e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855".to_string())
+                    Some(
+                        "e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855"
+                            .to_string(),
+                    )
                 };
-                
+
                 files.push(FileInfo {
                     filename,
                     file_size,
@@ -90,7 +94,7 @@ fn scan_directory_recursive(
                     relative_path,
                     upload_time,
                 });
-                
+
                 *total_size += file_size;
             } else if path.is_dir() {
                 scan_directory_recursive(base, &path, files, total_size);
@@ -102,11 +106,11 @@ fn scan_directory_recursive(
 pub fn compute_file_hash(path: &Path) -> Result<String, std::io::Error> {
     use sha2::{Digest, Sha256};
     use std::io::Read;
-    
+
     let mut file = std::fs::File::open(path)?;
     let mut hasher = Sha256::new();
     let mut buffer = [0u8; 8192];
-    
+
     loop {
         let bytes_read = file.read(&mut buffer)?;
         if bytes_read == 0 {
@@ -114,6 +118,6 @@ pub fn compute_file_hash(path: &Path) -> Result<String, std::io::Error> {
         }
         hasher.update(&buffer[..bytes_read]);
     }
-    
+
     Ok(format!("{:x}", hasher.finalize()))
-}
+}