Add missing fs/path/os imports in server/idea_generator.js

server/idea_generator.js

@@ -1,3 +1,6 @@
+import * as fs from "node:fs";
+import * as path from "node:path";
+import * as os from "node:os";
 import { spawn } from "node:child_process";
 import { GoogleGenAI } from "@google/genai";
 import { drawCards } from "./whack_cards.js";