fix(settings): the "open completed tasks" link was unstyled

It carried class="ghost", which nothing in the data page styles — so it
fell back to the browser's blue underline while every link beside it is
the accent-coloured .link. Now it matches them.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

web/src/routes/indstillinger/data/+page.svelte

@@ -285,7 +285,7 @@
 		<p class="hint">{t('data.doneHint')}</p>
 	</header>
 	<div class="row">
-		<a class="ghost" href="/faerdige">{t('data.openDone')}</a>
+		<a class="link" href="/faerdige">{t('data.openDone')}</a>
 	</div>
 </section>