refactor: apply 5-pass audit optimizations across mcp-memory codebase

server/src/handlers/logs.rs

@@ -64,10 +64,12 @@ impl McpTool for GetRecentLogsHandler {
             file.seek(SeekFrom::End(-(read_size as i64)))
                 .map_err(|e| e.to_string())?;
 
-            let mut buffer = String::new();
-            file.read_to_string(&mut buffer)
+            let mut vec_buf = Vec::new();
+            file.read_to_end(&mut vec_buf)
                 .map_err(|e| e.to_string())?;
 
+            let buffer = String::from_utf8_lossy(&vec_buf).to_string();
+
             let lines: Vec<&str> = buffer.lines().collect();
             let recent_lines = if lines.len() > 100 {
                 lines[lines.len() - 100..].join("\n")