feat(10-06): update StorageBrowser — skeleton rows, EmptyState, BreadcrumbBar swap

- Replace FolderBreadcrumb import with BreadcrumbBar + EmptyState imports
- Replace <FolderBreadcrumb> with <BreadcrumbBar :root-label="mode === 'cloud' ? 'Cloud' : 'Home'">
- Replace Loading… div with 5 animated skeleton rows (animate-pulse, grid-cols-[2rem_1fr_6rem_8rem_6rem])
- Replace inline empty-state divs with three <EmptyState> blocks (search/in-folder/root)
- UX-02 skeleton tests green (4/4)

frontend/src/components/storage/StorageBrowser.vue

@@ -4,8 +4,9 @@
     <!-- ── Sticky toolbar ──────────────────────────────────────────────── -->
     <div class="sticky top-0 z-10 bg-white border-b border-gray-100">
       <div class="px-6 py-3 flex items-center gap-3 flex-wrap">
-        <FolderBreadcrumb
+        <BreadcrumbBar
           :segments="breadcrumb"
+          :root-label="mode === 'cloud' ? 'Cloud' : 'Home'"
           @navigate="$emit('breadcrumb-navigate', $event)"
         />
         <div class="ml-auto flex items-center gap-2 shrink-0">
@@ -223,25 +224,46 @@
           </div>
         </div>
 
-        <!-- Empty state -->
-        <div
-          v-if="!loading && folders.length === 0 && files.length === 0 && !showNewFolderInput"
-          class="px-4 py-10 text-center text-gray-300"
-        >
-          <p class="text-gray-400 text-sm">{{ emptyMessage }}</p>
-          <p class="text-xs mt-1">{{ emptyHint }}</p>
-        </div>
+        <template v-if="loading">
+          <div
+            v-for="n in 5"
+            :key="`sk-${n}`"
+            class="px-4 py-2.5 grid grid-cols-[2rem_1fr_6rem_8rem_6rem] gap-3 items-center border-b border-gray-100"
+          >
+            <div class="w-7 h-7 bg-gray-100 rounded-lg animate-pulse"></div>
+            <div class="h-4 bg-gray-100 rounded animate-pulse w-2/3"></div>
+            <div class="h-3 bg-gray-100 rounded animate-pulse hidden md:block"></div>
+            <div class="h-3 bg-gray-100 rounded animate-pulse hidden sm:block"></div>
+            <div class="w-14 h-3 bg-gray-100 rounded animate-pulse"></div>
+          </div>
+        </template>
 
-        <!-- Search no-results -->
-        <div
-          v-else-if="searchQuery && files.length === 0 && folders.length === 0"
-          class="px-4 py-10 text-center text-sm text-gray-400"
+        <EmptyState
+          v-else-if="searchQuery && folders.length === 0 && files.length === 0"
+          icon="search"
+          :headline="`No results for &quot;${searchQuery}&quot;`"
+          subtext="Try a different search term or clear the filter."
         >
-          No items match "{{ searchQuery }}".
-        </div>
+          <template #cta>
+            <button @click="$emit('search-change', '')" class="mt-3 text-sm text-indigo-600 hover:underline">
+              Clear search
+            </button>
+          </template>
+        </EmptyState>
 
-        <!-- Loading -->
-        <div v-if="loading" class="py-6 text-center text-sm text-gray-400">Loading…</div>
+        <EmptyState
+          v-else-if="breadcrumb.length > 0 && folders.length === 0 && files.length === 0 && !showNewFolderInput"
+          icon="document"
+          :headline="emptyMessage"
+          :subtext="emptyHint"
+        />
+
+        <EmptyState
+          v-else-if="folders.length === 0 && files.length === 0 && !showNewFolderInput"
+          icon="folder"
+          :headline="emptyMessage"
+          :subtext="emptyHint"
+        />
       </div>
     </div>
   </div>
@@ -249,7 +271,8 @@
 
 <script setup>
 import { ref, computed, nextTick, onMounted, onUnmounted } from 'vue'
-import FolderBreadcrumb from '../folders/FolderBreadcrumb.vue'
+import BreadcrumbBar from '../ui/BreadcrumbBar.vue'
+import EmptyState from '../ui/EmptyState.vue'
 import SearchBar from '../documents/SearchBar.vue'
 import SortControls from '../documents/SortControls.vue'
 import DropZone from '../upload/DropZone.vue'