Add React frontend and clean up legacy HTTP backend

frontend/src/components/Trick.tsx

@@ -0,0 +1,26 @@
+import type { StashData } from '../types';
+import CardView from './CardView';
+
+interface Props {
+  stash: StashData | null;
+}
+
+export default function Trick({ stash }: Props) {
+  const cards = stash
+    ? [0, 1, 2, 3]
+        .map((i) => (stash.first_player + i) % 4)
+        .map((order) => stash.cards[String(order)])
+        .filter(Boolean)
+    : [];
+
+  return (
+    <div className="bg-green-900/60 rounded-xl p-4">
+      <p className="text-xs text-green-300 mb-3 text-center">Aktualny stich</p>
+      <div className="flex gap-3 justify-center min-h-28">
+        {cards.map((card, i) => (
+          <CardView key={i} card={card} size="lg" />
+        ))}
+      </div>
+    </div>
+  );
+}