feat: replace showcase tag overlays with ghost count badge, refine nav hint

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

app/static/style.css

@@ -1291,12 +1291,18 @@ header {
 }
 
 .showcase-nav .nav-hint {
-  color: rgba(255,255,255,0.4);
+  opacity: 0;
+  transition: opacity 0.2s ease;
   font-size: 0.8rem;
+  color: var(--text-muted);
   margin-top: 0.25rem;
   pointer-events: none;
 }
 
+.showcase-nav:hover .nav-hint {
+  opacity: 1;
+}
+
 /* Masonry container - JS-managed columns */
 .masonry-container {
   display: flex;
@@ -1349,6 +1355,35 @@ header {
   z-index: 2;
 }
 
+/* Ghost tag count badge on showcase items */
+.tag-count-badge {
+  position: absolute;
+  bottom: 8px;
+  right: 8px;
+  padding: 2px 7px;
+  border-radius: 999px;
+  background: rgba(0, 0, 0, 0.45);
+  border: 1px solid rgba(255, 255, 255, 0.15);
+  color: rgba(255, 255, 255, 0.55);
+  font-size: 0.7rem;
+  font-weight: 500;
+  z-index: 2;
+  pointer-events: none;
+  opacity: 0;
+  transition: opacity 0.2s ease;
+}
+
+.masonry-item:hover .tag-count-badge {
+  opacity: 1;
+}
+
+/* Touch devices: always show badge */
+@media (hover: none) {
+  .tag-count-badge {
+    opacity: 1;
+  }
+}
+
 /* Loading state for shuffle */
 .masonry-container.loading {
   opacity: 0.5;