Pasting into the prompt textarea left its layout stale until the next edit, so the visible content did not reflect the pasted text. Mark the layout dirty on paste and notify the content-change handler once the renderer is idle so the prompt updates immediately.
String.length counts code points, not display columns, so CJK
characters and emoji that occupy two terminal cells caused
misaligned cursors, broken mention triggers, and incorrect
history restoration offsets.
Use Bun.stringWidth for now, we need an alternative for this.
Fix#26716Close#26922
Simon Klee