feat: integrate Pi backend and Pi Web

pi-web/proxy.ts

@@ -0,0 +1,11 @@
+import { NextResponse, type NextRequest } from "next/server";
+import { isApiRequestAllowed } from "@/lib/request-security";
+
+export function proxy(request: NextRequest) {
+  if (!isApiRequestAllowed(request)) {
+    return NextResponse.json({ error: "Untrusted API request" }, { status: 403 });
+  }
+  return NextResponse.next();
+}
+
+export const config = { matcher: "/api/:path*" };