chore: install project dependencies and generate build artifacts.

frontend/app/api/cities/route.ts

@@ -0,0 +1,26 @@
+import { NextResponse } from "next/server";
+
+const API_BASE =
+  process.env.POLYWEATHER_API_BASE_URL || "http://127.0.0.1:8000";
+
+export async function GET() {
+  try {
+    const res = await fetch(`${API_BASE}/api/cities`, {
+      headers: { Accept: "application/json" },
+      next: { revalidate: 120 },
+    });
+    if (!res.ok) {
+      return NextResponse.json(
+        { error: `Backend returned ${res.status}` },
+        { status: 502 },
+      );
+    }
+    const data = await res.json();
+    return NextResponse.json(data);
+  } catch (error) {
+    return NextResponse.json(
+      { error: "Failed to fetch cities", detail: String(error) },
+      { status: 500 },
+    );
+  }
+}