fix assistant widget configuration

apps/nextjs/src/app/api/assistant/chat/assistant-openrouter.ts

@@ -0,0 +1,21 @@
+const openRouterWebSearchTool = {
+  type: "openrouter:web_search",
+  parameters: { max_results: 5 },
+} as const;
+
+export const withOpenRouterWebSearch = (body: Record<string, unknown>) => {
+  const tools = Array.isArray(body.tools) ? body.tools : [];
+  if (
+    tools.some(
+      (candidate) =>
+        typeof candidate === "object" &&
+        candidate !== null &&
+        "type" in candidate &&
+        candidate.type === openRouterWebSearchTool.type,
+    )
+  ) {
+    return body;
+  }
+
+  return { ...body, tools: [...tools, openRouterWebSearchTool] };
+};