Add loading skeletons for search results

Replace bare 'Searching…' text with 8 animated skeleton cards that
mirror the real card layout (thumbnail, title, channel, menu dot).
Shimmer animation sweeps across placeholder blocks until results arrive.

Files:
- frontend/app.js: showSearchSkeletons() function, wired into search submit
- frontend/styles.css: .skeleton-card, .skeleton-shimmer, .skeleton-line, .skeleton-dot styles with shimmer animation

BACKLOG.md

@@ -16,7 +16,7 @@ bottom as they come up.
 
 ## UX / polish
 - [x] Empty-state designs for empty playlists and empty history (match the new hero).
-- [ ] Loading skeletons for search results instead of a bare "Searching…".
+- [x] Loading skeletons for search results instead of a bare "Searching…".
 - [ ] Keyboard-shortcut help overlay (press `?`), listing space / arrows / f / m.
 - [ ] Download/preload progress indicator on cards (percent or a bar, not just a pulse).
 - [ ] Remember and restore the last playback position per video.

frontend/app.js

@@ -561,6 +561,23 @@ function currentList() {
   return [];
 }
 
+function showSearchSkeletons() {
+  els.status.classList.add('hidden');
+  els.cards.innerHTML = '';
+  for (let i = 0; i < 8; i++) {
+    const s = document.createElement('div');
+    s.className = 'card skeleton-card';
+    s.innerHTML = `
+      <div class="thumb skeleton-shimmer"></div>
+      <div class="card-info">
+        <div class="skeleton-line skeleton-shimmer" style="width:85%"></div>
+        <div class="skeleton-line skeleton-shimmer" style="width:55%;margin-top:8px"></div>
+      </div>
+      <div class="skeleton-dot skeleton-shimmer"></div>`;
+    els.cards.appendChild(s);
+  }
+}
+
 function renderList() {
   if (view.type === 'settings') { renderSettings(); return; }
 
@@ -956,15 +973,15 @@ function wireUI() {
     if (!q) return;
     view = { type: 'search' };
     render();
-    els.status.classList.remove('hidden');
-    els.status.textContent = 'Searching…';
-    els.cards.innerHTML = '';
+    showSearchSkeletons();
     try {
       const res = await API.search(q);
       if (!res || !res.ok) throw new Error(res?.error || 'Search failed');
       searchResults = res.results || [];
       renderList();
     } catch (err) {
+      els.cards.innerHTML = '';
+      els.status.classList.remove('hidden');
       els.status.textContent = '⚠ ' + err.message;
     }
   });

frontend/styles.css

@@ -558,6 +558,53 @@ input[type="range"]::-webkit-slider-thumb:hover { transform: scale(1.25); }
 
 .status { padding: 16px 20px; color: var(--text-dim); font-size: 13px; }
 
+/* ===================== Skeleton loading ===================== */
+.skeleton-card {
+  cursor: default !important;
+  pointer-events: none;
+  border-color: transparent !important;
+  animation: cardIn 0.45s var(--ease) backwards !important;
+}
+.skeleton-shimmer {
+  position: relative;
+  overflow: hidden;
+  background: var(--bg-3);
+  border-radius: 9px;
+}
+.skeleton-shimmer::after {
+  content: "";
+  position: absolute;
+  inset: 0;
+  background: linear-gradient(
+    90deg,
+    transparent,
+    rgba(255,255,255,0.04) 40%,
+    rgba(255,255,255,0.07) 50%,
+    rgba(255,255,255,0.04) 60%,
+    transparent
+  );
+  animation: shimmer 1.6s ease-in-out infinite;
+}
+@keyframes shimmer {
+  0% { transform: translateX(-100%); }
+  100% { transform: translateX(100%); }
+}
+.skeleton-card .thumb {
+  background: var(--bg-3);
+}
+.skeleton-line {
+  height: 14px;
+  width: 100%;
+  border-radius: 8px;
+}
+.skeleton-dot {
+  width: 32px;
+  height: 32px;
+  border-radius: 8px;
+  align-self: center;
+  flex-shrink: 0;
+}
+
 /* ===================== Empty state ===================== */
 .empty-state {
   display: flex;