Merge branch 'hopper-vc6iumln-chat-bar-response-above'
Refined chat bar response panel: CSS class toggle transition
instead of display:none, smooth max-height expansion, separator
element, and repositioned dismiss button with updated styling.
Conflicts resolved by taking the feature branch versions of
convey/static/app.css and convey/templates/app.html, as the
feature branch is the refined iteration of the same work that
was partially landed in 50532ca5.