feat(lexware): add integration foundation

frontend/athena/app/api/repairs/[id]/estimates/[estimateId]/lexware/prepare-invoice/route.ts

@@ -0,0 +1,19 @@
+import { NextRequest } from "next/server";
+
+import { proxyHermesRequest } from "@/lib/server/hermes-proxy";
+import { assertSameOrigin } from "@/lib/server/request-guards";
+
+type Params = {
+  params: Promise<{ id: string; estimateId: string }>;
+};
+
+export async function POST(request: NextRequest, { params }: Params) {
+  const originError = assertSameOrigin(request);
+
+  if (originError) {
+    return originError;
+  }
+
+  const { id, estimateId } = await params;
+  return proxyHermesRequest(request, `/repairs/${id}/estimates/${estimateId}/lexware/prepare-invoice`);
+}