feat: Introduce a new Next.js modern frontend with a history API route and include legacy static assets.

frontend/app/api/history/[name]/route.ts

@@ -0,0 +1,39 @@
+import { NextResponse } from "next/server";
+
+const API_BASE = process.env.POLYWEATHER_API_BASE_URL;
+
+export async function GET(
+  _req: Request,
+  context: { params: Promise<{ name: string }> },
+) {
+  if (!API_BASE) {
+    return NextResponse.json(
+      { error: "POLYWEATHER_API_BASE_URL is not configured" },
+      { status: 500 },
+    );
+  }
+
+  const { name } = await context.params;
+  const url = `${API_BASE}/api/history/${encodeURIComponent(name)}`;
+
+  try {
+    const res = await fetch(url, {
+      headers: { Accept: "application/json" },
+      cache: "no-store",
+    });
+    if (!res.ok) {
+      const raw = await res.text();
+      return NextResponse.json(
+        { error: `Backend returned ${res.status}`, detail: raw.slice(0, 300) },
+        { status: 502 },
+      );
+    }
+    const data = await res.json();
+    return NextResponse.json(data);
+  } catch (error) {
+    return NextResponse.json(
+      { error: "Failed to fetch history", detail: String(error) },
+      { status: 500 },
+    );
+  }
+}

frontend/app/modern/page.tsx

@@ -0,0 +1,5 @@
+import { PolyWeatherDashboard } from "@/components/polyweather-dashboard";
+
+export default function ModernPage() {
+  return <PolyWeatherDashboard />;
+}

frontend/app/page.tsx

@@ -1,5 +1,11 @@
-import { PolyWeatherDashboard } from "@/components/polyweather-dashboard";
-
 export default function HomePage() {
-  return <PolyWeatherDashboard />;
+  return (
+    <main className="h-screen w-screen overflow-hidden bg-black">
+      <iframe
+        title="PolyWeather Legacy Dashboard"
+        src="/legacy/index.html"
+        className="h-full w-full border-0"
+      />
+    </main>
+  );
 }