Copy the feed URL by clicking the box it sits inUnverified

The address is the one thing on that page worth taking away, and
taking it away meant dragging across a line of monospace and hoping
the selection landed on the whole of it. Make the box around it the
button: the box is what reads as one thing to press, and the URL is a
thin line of type to aim at.

It is an upgrade, not a requirement. The markup ships as a box with a
URL in it, and the script is what turns that into a control - the
role, the tab stop, the name a screen reader reads, the pointer, and
the "click to copy" in the corner all arrive together, written by the
code that implements them. A page whose script never ran offers no
press it cannot honour; the URL is still selectable text, still
user-select:all, and still says the same thing.

What the clipboard cannot say for itself, the toast says: the word
"Copied", in the corner, gone a second later, taking nothing with it
on the way out because it never occupied any space. Behind it,
navigator.clipboard where it is allowed and execCommand over a
selection where it is not, and if even that fails the URL is left
selected rather than the page claiming a copy that did not happen.

The behaviour lives in one file that both renderings of the page pull
in - the stylesheet as a deferred <script src>, the standby inlined by
Hugo and called by hand once it has built the document - because the
page is already written twice and its one piece of behaviour need not
be. What it says is on the element it upgrades, in data attributes, so
no string is spelled out in the script and every language keeps its
own. It builds the toast with createElementNS: on the standby path
this runs inside index.xml, where createElement makes an element in no
namespace at all, and nothing renders.