🔒 Fix Prototype Pollution in setNested

[akutuva21]

🎯 What: The setNested function in scripts/generate-manifest.js was vulnerable to Prototype Pollution. It allowed malicious payloads to construct or modify paths containing __proto__, constructor, or prototype, traversing up to the global prototype object.

⚠️ Risk: If an attacker provided a crafted input, they could manipulate the global Object.prototype. This can lead to arbitrary code execution, denial of service (DoS), or logic manipulation of the JavaScript runtime.

🛡️ Solution: Added an explicit check within the traversal loop to skip (continue) any key matching __proto__, constructor, or prototype. Additionally, applied the same check to the final assignment step (return early) so that the global prototype/constructor itself cannot be re-assigned. This completely mitigates the vulnerability in setNested.

---

PR created automatically by Jules for task 15072088604429859966 started by @akutuva21

[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.

[akutuva21]

Reviewed in sequence. Branch now hardens nested-key assignment consistently in both metadata parsers, closing the prototype-pollution gap.