docs: Zusatzfunktionen (Kai, 25.06.2025) in TODO.md ergänzt

pages/api/cpl/updateKueSettingsDataAPIHandler.ts

@@ -1,12 +1,21 @@
 // /pages/api/cpl/updateKueSettingsDataAPIHandler.ts
 import path from "path";
 import fs from "fs/promises";
+import type { NextApiRequest, NextApiResponse } from "next";
+export default async function handler(
+  req: NextApiRequest,
+  res: NextApiResponse
+) {
+  let { key, value, slot } = req.query;
 
-export default async function handler(req, res) {
-  const { key, value, slot } = req.query;
-
-  if (!key || slot === undefined) {
-    return res.status(400).json({ error: "Missing key or slot parameter." });
+  if (
+    typeof key !== "string" ||
+    typeof value !== "string" ||
+    typeof slot !== "string"
+  ) {
+    return res
+      .status(400)
+      .json({ error: "Missing or invalid key, value, or slot parameter." });
   }
 
   const mockFilePath = path.join(