Style: Unify cart Continue Shopping button with wishlist style

Updated cart dropdown Continue Shopping buttons to use btn-outline
class (matching wishlist style) instead of btn-text across all pages.

Changes:
- shop.html: btn-text → btn-outline
- contact.html: btn-text → btn-outline
- product.html: btn-text → btn-outline
- about.html: btn-text → btn-outline

All cart Continue Shopping buttons now have consistent styling
with the wishlist Continue Shopping button (purple outline style).

website/public/product.html

@@ -153,7 +153,7 @@
                 <a href="/checkout" class="btn-primary-full"
                   >Proceed to Checkout</a
                 >
-                <a href="/shop" class="btn-text">Continue Shopping</a>
+                <a href="/shop" class="btn-outline">Continue Shopping</a>
               </div>
             </div>
           </div>
@@ -259,7 +259,9 @@
             "Fetching product from API:",
             `/api/products/${productId}`
           );
-          const response = await window.apiCache.fetch(`/api/products/${productId}`);
+          const response = await window.apiCache.fetch(
+            `/api/products/${productId}`
+          );
           const data = await response.json();
           console.log("API response:", data);