MAESTRO: fix lint issues

frontend/src/components/CaptchaChallenge.tsx

@@ -189,6 +189,7 @@ export default function CaptchaChallenge({
 
         <div className="mt-5 flex flex-col gap-4">
           <div className="rounded-xl border border-info/20 bg-background/50 p-4">
+            {/* eslint-disable-next-line @next/next/no-img-element */}
             <img
               src={`data:image/png;base64,${challenge.imageBase64}`}
               alt="CAPTCHA challenge"

frontend/vitest.setup.ts

@@ -1,5 +1,5 @@
 const createLocalStorageMock = () => {
-  let store = new Map<string, string>();
+  const store = new Map<string, string>();
 
   return {
     get length() {