fix(template): stop rendering the sort dropdown in its opened state

[culfin]

ui/template/sort-btns.html carries the DOM of an opened dropdown:

<div role="group" class="show dropdown btn-group">
  <button type="button" aria-expanded="true" class="dropdown-toggle show btn …">
  <div x-placement="bottom-start" class="dropdown-menu show"
       data-popper-reference-hidden="false" data-popper-escaped="false"
       data-popper-placement="bottom-start"
       style="position: absolute; inset: 0px auto auto 0px; transform: translate(0px, 33px);">

class="show" sits on the group, the toggle and the menu; aria-expanded says
true; and the inline style is the position Popper had computed at the moment
that markup was captured.

Without the React interface — the situation the template exists for — the menu
stands open across the page, and assistive technology is told that a collapsed
control is expanded.

The same file holds a captured React identifier as well:

<button type="button" id="react-aria8245013726-:r5:" …>
<div … aria-labelledby="react-aria8245013726-:r5:" …>

It works, but it is not a name anyone chose, and the colons make it awkward to
address from CSS. Replaced with question-layout-toggle.

How it was found

Building a site that shows the server-rendered pages to visitors rather than
only to crawlers. Until the interface loads, "Score" hangs over the question
list.

🤖 Generated with Claude Code

[culfin]

Folded into #1592 together with the other three defects in ui/template/ — one pull request is easier to review than four, and none of them is more than a line or two. Nothing is dropped, and the new one also targets dev as requested in #1572. Closing to keep the queue readable.