fix massege box with non ascii carecters

[naattxx]

fix #119 using Buffer.byteLength(str, 'utf8')

[JumpLink]

@naattxx thanks for the fix! 🙂 The root cause is exactly right, but please don't pull in Node.js modules here: the app runs on GJS, not Node.js, and node:buffer would just bloat the bundle (even though it is still possible to use Node.js modules with GJSify).

The fix works without any dependency, just pass -1 and GTK figures out the byte length itself:

  this._textView.buffer.insert_at_cursor(message, -1);

Could you change that and revert the @types/node / tsconfig / lockfile changes? Then this is good to go 👍