Plain Ctrl+V was never the terminal's: it went to the pty as a literal ^V
(0x16) — the command history even recorded 'cd \u0016' — so nothing pasted
and the confirm dialog never saw it. It is now handled on the terminal host
in the capture phase, with preventDefault, feeding the same path as
Ctrl+Shift+V.
The paste check is now shape-based rather than length-based: two or more
lines confirm (a stray newline executes an unreviewed command), a single
line pastes straight through unless it is unusually long.