feat(showcase): add Show button to NSFW notice in main media area

- Add showcase__nsfw-notice-content wrapper for better layout
- Add showcase__nsfw-show-btn with styling matching card.css show-content-btn
- Add show-content action handler that triggers global blur toggle
- Button uses blue accent color with eye icon and hover effects
- Clicking Show button syncs with blur toggle button icon state
- Use unique class names to avoid conflicts with card.css

static/css/components/model-modal/thumbnail-rail.css

@@ -55,7 +55,12 @@
   object-fit: cover;
 }
 
-/* NSFW blur */
+/* NSFW blur for thumbnails - BEM naming to avoid conflicts with global .nsfw-blur */
+.thumbnail-rail__item--nsfw-blurred img {
+  filter: blur(8px);
+}
+
+/* Legacy support for old class names (deprecated) */
 .thumbnail-rail__item.nsfw img {
   filter: blur(8px);
 }
@@ -72,6 +77,8 @@
   border-radius: var(--border-radius-xs);
   text-transform: uppercase;
   letter-spacing: 0.05em;
+  pointer-events: none;
+  user-select: none;
 }
 
 /* Add button */