Feature.link: a card's name may point elsewhere

An https URL on a feature renders its name as an outbound link -
an announcement's programme page, a venue. Validated on load.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

src/app.rs

@@ -945,7 +945,16 @@ fn AlternativeCard(
                                         let name = feature.name.clone();
                                         move || !name.is_empty()
                                     }>
-                                        <h3>{feature.name.clone()}</h3>
+                                        <h3>
+                                            {match feature.link.clone() {
+                                                Some(href) => view! {
+                                                    <a href=href target="_blank" rel="noopener noreferrer">
+                                                        {feature.name.clone()}
+                                                    </a>
+                                                }.into_any(),
+                                                None => feature.name.clone().into_any(),
+                                            }}
+                                        </h3>
                                     </Show>
                                     <Show when={
                                         let description = feature.description.clone();