remove counter of selected feed

vue/src/components/AppNav.vue

@@ -10,6 +10,24 @@ const { sync, showModal, viewMode, toggleViewMode, layout, toggleLayout, markAll
 
 const headerRef = ref(null)
 
+// Native <select>/<option> has no "is open" state — the closed box just shows
+// the selected option's text verbatim, so per-option unread counts can only be
+// toggled based on focus, since the popup is only ever shown while focused.
+// @focus ~ opening (shows counts); @change (picking an option closes the
+// popup but keeps focus, so no blur fires) and @blur (focus left without
+// picking) ~ closed (counts hidden, so the closed box just shows the name).
+const filterOpen = ref(false)
+
+function onFilterFocus() {
+  filterOpen.value = true
+  refreshUnreadDisplay()
+}
+
+function onFilterChange(event) {
+  setFeedFilter(event.target.value || null)
+  filterOpen.value = false
+}
+
 // Scroll-driven show/hide: the header slides out of view on scroll-down and
 // back in on scroll-up. This is show/hide via `transform` (not the old
 // resize behaviour) — the header is position:fixed, so translating it never
@@ -165,11 +183,12 @@ function handleToggleLayout() {
         class="app-nav__filter"
         :value="feedFilter ?? ''"
         aria-label="Filter by feed"
-        @focus="refreshUnreadDisplay"
-        @change="setFeedFilter($event.target.value || null)"
+        @focus="onFilterFocus"
+        @change="onFilterChange"
+        @blur="filterOpen = false"
       >
         <option value="">All feeds</option>
-        <option v-for="title in feedTitles" :key="title" :value="title">{{ title }} ({{ displayedFeedUnreadCounts[title] ?? 0 }})</option>
+        <option v-for="title in feedTitles" :key="title" :value="title">{{ title }}<template v-if="filterOpen"> ({{ displayedFeedUnreadCounts[title] ?? 0 }})</template></option>
       </select>
       <button
         class="app-nav__hamburger"