Wire up remaining placeholder settings, implement menu search (v2.4.0)

- Custom dashboard, Modern plugins page, and Modern comments page
  toggles previously had no effect at all — their respective takeovers/
  redirects (DashboardTakeover, SubApps' Plugins/Comments handling,
  MenuSerializer's link rewrites) ran unconditionally regardless of the
  setting. All three now default to their previous always-on behavior
  but can actually be turned off.
- Menu search had zero implementation. Sidebar.vue now shows a real
  search box (gated on the setting) that filters both the WP-native menu
  and the Aurora nav section by title, auto-expanding matching sections.
- Removed "Modern posts table" and "Modern users page" toggles (and
  their now-empty Posts/Users settings categories) — both described a
  custom management page that was never built. A checkbox with nothing
  behind it is worse than no checkbox.

Verified all four live: dashboard/plugins/comments toggles correctly
flip between the Aurora and native experience and back; menu search
filters correctly and clears back to the full menu.

Co-Authored-By: Claude Sonnet 5 <[email protected]>

app/src/shell/components/Sidebar.vue

@@ -86,13 +86,13 @@ const openId = ref(
       : null)
 );
 
-const isExpanded = (item) => openId.value === item.id;
+const isExpanded = (item) => isSearching.value || openId.value === item.id;
 
 const toggle = (item) => {
   openId.value = openId.value === item.id ? null : item.id;
 };
 
-const auroraExpanded = computed(() => openId.value === AURORA_ID);
+const auroraExpanded = computed(() => isSearching.value || openId.value === AURORA_ID);
 const toggleAuroraNav = () => {
   openId.value = auroraExpanded.value ? null : AURORA_ID;
   // Only Aurora's own expand state needs to persist across page loads —
@@ -101,6 +101,34 @@ const toggleAuroraNav = () => {
   localStorage.setItem('aurora-nav-expanded', auroraExpanded.value ? '1' : '0');
 };
 const isAuroraActive = (item) => normalize(item.url) === current.value;
+
+// Settings > Menu > "Show a search box at the top of the admin menu" —
+// filters both the WP-native menu list and the Aurora nav section by
+// title (own item or any submenu item), auto-expanding every section with
+// a match so results are visible without also having to click into them.
+const showMenuSearch = computed(() => !!props.serverData?.settings?.menu_search);
+const searchQuery = ref('');
+const isSearching = computed(() => searchQuery.value.trim() !== '');
+const matchesQuery = (text) =>
+  (text || '').toLowerCase().includes(searchQuery.value.trim().toLowerCase());
+
+const filteredMenu = computed(() => {
+  if (!isSearching.value) return props.menu;
+  return props.menu
+    .filter((item) => !item.separator)
+    .map((item) => {
+      const titleMatch = matchesQuery(item.title);
+      const matchingSubs = (item.submenu || []).filter((sub) => matchesQuery(sub.title));
+      if (!titleMatch && !matchingSubs.length) return null;
+      return titleMatch ? item : { ...item, submenu: matchingSubs };
+    })
+    .filter(Boolean);
+});
+
+const filteredAuroraNav = computed(() => {
+  if (!isSearching.value) return props.auroraNav;
+  return props.auroraNav.filter((item) => matchesQuery(item.title));
+});
 </script>
 
 <template>
@@ -111,8 +139,13 @@ const isAuroraActive = (item) => normalize(item.url) === current.value;
       <template v-else>{{ collapsed ? 'A' : 'Aurora' }}</template>
     </div>
 
+    <div v-if="showMenuSearch && !collapsed" class="sidebar__menu-search">
+      <span class="dashicons dashicons-search" />
+      <input v-model="searchQuery" type="text" placeholder="Search menu…" />
+    </div>
+
     <ul class="sidebar__list">
-      <template v-for="(item, index) in menu" :key="item.id || index">
+      <template v-for="(item, index) in filteredMenu" :key="item.id || index">
         <li v-if="item.separator" class="sidebar__separator" />
 
         <li v-else class="sidebar__item">
@@ -139,7 +172,7 @@ const isAuroraActive = (item) => normalize(item.url) === current.value;
               <span v-if="item.count" class="sidebar__count">{{ item.count }}</span>
             </a>
             <button
-              v-if="item.submenu && item.submenu.length"
+              v-if="item.submenu && item.submenu.length && !isSearching"
               type="button"
               class="sidebar__chevron"
               :class="{ 'sidebar__chevron--open': isExpanded(item) }"
@@ -173,9 +206,13 @@ const isAuroraActive = (item) => normalize(item.url) === current.value;
       </template>
     </ul>
 
-    <div v-if="auroraNav.length" class="sidebar__separator" />
+    <p v-if="isSearching && !filteredMenu.length && !filteredAuroraNav.length" class="sidebar__no-results">
+      No matching menu items.
+    </p>
 
-    <div v-if="auroraNav.length" class="sidebar__aurora">
+    <div v-if="filteredAuroraNav.length" class="sidebar__separator" />
+
+    <div v-if="filteredAuroraNav.length" class="sidebar__aurora">
       <div class="sidebar__row sidebar__aurora-brand" @click="toggleAuroraNav">
         <a href="#" class="sidebar__link" @click.prevent :title="collapsed ? 'Aurora' : null">
           <span class="sidebar__icon">
@@ -184,6 +221,7 @@ const isAuroraActive = (item) => normalize(item.url) === current.value;
           <span class="sidebar__title">Aurora</span>
         </a>
         <button
+          v-if="!isSearching"
           type="button"
           class="sidebar__chevron"
           :class="{ 'sidebar__chevron--open': auroraExpanded }"
@@ -194,7 +232,7 @@ const isAuroraActive = (item) => normalize(item.url) === current.value;
       </div>
 
       <ul v-if="auroraExpanded" class="sidebar__sublist">
-        <li v-for="item in auroraNav" :key="item.id" class="sidebar__subitem">
+        <li v-for="item in filteredAuroraNav" :key="item.id" class="sidebar__subitem">
           <a
             :href="item.url"
             class="sidebar__sublink"
@@ -265,6 +303,41 @@ const isAuroraActive = (item) => normalize(item.url) === current.value;
   object-fit: contain;
 }
 
+.sidebar__menu-search {
+  display: flex;
+  align-items: center;
+  gap: 8px;
+  margin: 0 12px 10px;
+  padding: 6px 10px;
+  border-radius: 8px;
+  background: var(--aurora-bg-subtle);
+  color: var(--aurora-text-muted);
+}
+.sidebar__menu-search .dashicons {
+  font-size: 15px;
+  width: 15px;
+  height: 15px;
+  flex-shrink: 0;
+}
+.sidebar__menu-search input {
+  flex: 1;
+  min-width: 0;
+  border: none;
+  background: none;
+  outline: none;
+  color: var(--aurora-text);
+  font-size: 0.8125rem;
+}
+.sidebar__menu-search input::placeholder {
+  color: var(--aurora-text-muted);
+}
+
+.sidebar__no-results {
+  margin: 4px 16px;
+  font-size: 0.8125rem;
+  color: var(--aurora-text-muted);
+}
+
 .sidebar__list,
 .sidebar__sublist {
   list-style: none;