fix: don't steal focus from search input during focus restoration

When typing in the search bar on a detail page, navigating to search
results would trigger restoreFocusForPage(), which focused the 'last
viewed' card and interrupted typing. Skip focus restoration whenever
the search input is currently the active element.

frontend/src/App.vue

@@ -412,6 +412,10 @@ function saveFocusForPage(page: string) {
 
 // Restore focus state for a page, or find the last viewed item
 function restoreFocusForPage(page: string) {
+  // Don't steal focus from the search input while the user is typing
+  const active = document.activeElement
+  if (active?.closest(".header-search")) return
+
   // First try to find the last viewed item and focus it
   if (lastViewedItemId.value) {
     // Use nextTick + timeout to ensure DOM is updated after navigation