Show a Deploy label in the artifact panel header when there's room (#2455)
* Show a Deploy label in the artifact header when the panel is wide enough
The deploy action was icon-only, which made it easy to miss. The panel is
user-resizable, so a viewport media query would be wrong here: gate the
label on a container query over the header itself, and collapse back to
the bare rocket on narrow panels and on mobile.
* Move the deploy button to the head of the artifact action cluster
It's the promoted action and the only labeled control in the group, so
placing it next to the tab switcher keeps copy/download/expand/close as
one uniform icon-only run.