Fix search module not showing on desktop

Remove Bootstrap collapse classes that were hiding the search on
desktop. Use CSS media queries instead: hidden on mobile by default,
visible on desktop. JS toggles .show class on mobile via the
search-toggler button.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/index.php

@@ -451,7 +451,7 @@ $wa->useScript('user.js');         // js/user.js
 				<button class="search-toggler d-lg-none" type="button" data-bs-toggle="collapse" data-bs-target="#headerSearchCollapse" aria-controls="headerSearchCollapse" aria-expanded="false" aria-label="<?php echo Text::_('JSEARCH_FILTER_SUBMIT'); ?>">
 					<span class="fa-solid fa-magnifying-glass" aria-hidden="true"></span>
 				</button>
-				<div class="container-search collapse d-lg-block" id="headerSearchCollapse">
+				<div class="container-search" id="headerSearchCollapse">
 					<jdoc:include type="modules" name="search" style="none" />
 				</div>
 			<?php endif; ?>