🛡️ Sentinel: [HIGH] Fix XSS vulnerabilities in magic link callback

[secrooq]

🚨 Severity: HIGH
💡 Vulnerability: Cross-Site Scripting (XSS). The src/app/api/auth/magic/callback/route.ts API route returns a raw HTML string. Two XSS vectors were found:

1. DOM-based XSS: User input was appended to a log box using div.innerHTML.
2. Reflected XSS: User-supplied email and token query parameters were injected directly into an inline <script> block via JSON.stringify() without escaping HTML tags, allowing an attacker to break out with </script>.

🎯 Impact: If exploited, an attacker could craft a malicious magic link. When clicked by a victim, arbitrary JavaScript could execute in the context of the application, potentially leading to session hijacking or unauthorized actions.

🔧 Fix:

1. Replaced div.innerHTML with div.textContent for the client-side log rendering.
2. Appended .replace(/</g, '\\u003c').replace(/>/g, '\\u003e') to the JSON.stringify() calls to properly encode HTML tags inside the JavaScript string context.

✅ Verification: Verified by running pnpm test, npx playwright test, and pnpm run build. All core tests pass and the application builds successfully.

---

PR created automatically by Jules for task 13966788033555062294 started by @secrooq

[google-labs-jules]

👋 Jules, reporting for duty! I'm here to lend a hand with this pull request.

When you start a review, I'll add a 👀 emoji to each comment to let you know I've read it. I'll focus on feedback directed at me and will do my best to stay out of conversations between you and other bots or reviewers to keep the noise down.

I'll push a commit with your requested changes shortly after. Please note there might be a delay between these steps, but rest assured I'm on the job!

For more direct control, you can switch me to Reactive Mode. When this mode is on, I will only act on comments where you specifically mention me with @jules. You can find this option in the Pull Request section of your global Jules UI settings. You can always switch back!

New to Jules? Learn more at jules.google/docs.

---

For security, I will only act on instructions from the user who triggered this task.