fix(install): suppress command echo in Windows native cmd shim

Add `@` prefix to the execution line in `native_cmd_shim` to prevent
cmd.exe from echoing the full command path before running it. Without
this, bun commands on Windows print the raw shim path in output.

Author: fengmk2

crates/vite_install/src/shim.rs

@@ -56,7 +56,7 @@ pub fn native_cmd_shim(relative_file: &str) -> String {
     formatdoc! {
         r#"
         @SETLOCAL
-        "%~dp0\{relative_file}" %*
+        @"%~dp0\{relative_file}" %*
         "#,
         relative_file = relative_file.replace('/', "\\")
     }