added frontend and made it usable

frontend/templates/events/_card.html.twig

@@ -0,0 +1,21 @@
+{% set category = event.categoryNames|first %}
+{% set image = event.primaryImage %}
+<a class="event-card" href="{{ path('event_show', {id: event.id}) }}">
+  {% if image %}
+    <div class="glyph-tile" style="padding:0;">
+      <img src="{{ image.storagePath }}" alt="" loading="lazy" style="position:absolute; inset:0; width:100%; height:100%; object-fit:cover;">
+    </div>
+  {% else %}
+    <div class="glyph-tile" style="background:{{ category|category_bg }}; color:{{ category|category_color }};">
+      <svg viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="1.6"><circle cx="12" cy="12" r="9"/><path d="M12 3v18M3 12h18"/></svg>
+    </div>
+  {% endif %}
+  <div class="body">
+    {% if category %}
+      <span class="tag" style="background:{{ category|category_bg }}; color:{{ category|category_color }};">{{ category }}</span>
+    {% endif %}
+    <h3>{{ event.title }}</h3>
+    <p class="when">{{ event.startDateTime ? event.startDateTime|date('D, M j · H:i') : 'Date TBD' }}</p>
+    <p class="place">{{ [event.street, event.city]|filter(v => v)|join(', ') ?: event.country }}</p>
+  </div>
+</a>