feat: smartin3.de gallery — add VW Golf MK1 cover photo with caption

Add real product photo (VW Golf MK1 trunk cover) to gallery with
description. Extend gallery CSS to support figcaption elements.

sites/smartin3.de/index.html

@@ -228,6 +228,40 @@
       display: block;
     }
 
+    .gallery-item figcaption {
+      padding: 12px 14px;
+      font-size: 0.78rem;
+      color: var(--text-dim);
+      line-height: 1.5;
+      font-weight: 300;
+      background: var(--bg-card);
+    }
+
+    .gallery-item figcaption strong {
+      color: var(--text);
+      font-weight: 500;
+      display: block;
+      margin-bottom: 4px;
+      font-family: 'Space Grotesk', sans-serif;
+      font-size: 0.82rem;
+    }
+
+    .gallery-item figure {
+      margin: 0;
+      height: 100%;
+      display: flex;
+      flex-direction: column;
+    }
+
+    .gallery-item figure img {
+      flex: 1;
+      min-height: 0;
+    }
+
+    .gallery-item.has-caption {
+      aspect-ratio: auto;
+    }
+
     @media (max-width: 640px) {
       .gallery-grid { grid-template-columns: repeat(2, 1fr); }
     }
@@ -394,8 +428,14 @@
       </div>
 
       <div class="gallery-grid">
-        <div class="gallery-item">
-          <img src="https://images.unsplash.com/photo-1636955816868-fcb881e57954?w=600&h=450&fit=crop" alt="3D-Druck Prototyp">
+        <div class="gallery-item has-caption">
+          <figure>
+            <img src="img/vw-golf-mk1-abdeckung.jpg" alt="VW Golf MK1 Kofferraumklappe Abdeckung">
+            <figcaption>
+              <strong>VW Golf MK1 Kofferraumklappe</strong>
+              Abdeckung fuer die offenen Loecher in der Kofferraumklappe des alten Golfs. Auf Wunsch auch mit Kunstleder oder anderen Folien lieferbar.
+            </figcaption>
+          </figure>
         </div>
         <div class="gallery-item">
           <img src="https://images.unsplash.com/photo-1612815154858-60aa4c59eaa6?w=600&h=450&fit=crop" alt="3D-Drucker bei der Arbeit">