refactor: apply zero-unwrap policy and optimize locks in store.rs and handlers

win-nvim/tests/integration_test.rs

@@ -1,5 +1,5 @@
 use serde_json::{json, Value};
-use std::io::{BufRead, BufReader, Read, Write};
+use std::io::{BufRead, BufReader, Write};
 use std::process::{Command, Stdio};
 
 fn send_message(stdin: &mut std::process::ChildStdin, msg: Value) {