resize method
Pins the terminal to an explicit cols×rows (no-op in xterm when
unchanged, so it won't spuriously fire a resize event). Guarded like the
other JS calls in case it lands on a not-yet-ready or disposed terminal.
Implementation
void resize(int cols, int rows) {
try {
_term.resize(cols, rows);
} on Object {
// Terminal not ready (or already disposed); a later fit will reconcile.
}
}