web: adopt Cache Components, Partial Prefetching and ensureStatic

web/src/components/layout/SeasonalHeader.tsx

@@ -0,0 +1,20 @@
+import { getToday } from "@/lib/today";
+import { Header } from "./Header";
+
+// The logo's hats depend on today's date, which the prerendered Header
+// (a Client Component) can't read itself
+export async function SeasonalHeader() {
+  const today = await getToday();
+
+  // let's add a santa hat during December
+  const christmas = today.getMonth() === 11;
+
+  // let's add the student hat during STUDiO 2026
+  const studentHat =
+    today.getFullYear() === 2026 &&
+    today.getMonth() === 7 &&
+    today.getDate() >= 10 &&
+    today.getDate() <= 16;
+
+  return <Header christmas={christmas} studentHat={studentHat} />;
+}