You could either modify the static HTML that is generated or dynamically apply the listener using vanilla JavaScript or jQuery. I'd recommend the latter.
You can just add the needed code to the body_footer key of the content array like so:
if (!isset($qa_content['body_footer'])) {
$qa_content['body_footer'] = '';
}
$qa_content['body_footer'] .= '<script>//your code</script>';
Note I'm being defensive on how I treat the body_footer array key presence.
Using JavaScript you can also add a <p> after the text input of the title.
You can also get the maximum length of the title using qa_opt('max_len_q_title'). Again, echo that output inside your script tags.