🛡️ Sentinel: Fix URL protocol validation in announcements

[one-more-refactor]

🚨 Severity: HIGH
💡 Vulnerability: Naive .startsWith() string matching was used for announcement link protocol validation, which can be bypassed via embedded ASCII control characters (e.g. null bytes \x00) or non-standard protocol formats.
🎯 Impact: Attackers could bypass URL validation to inject malicious client-side protocols (javascript:, data:, etc.) leading to Cross-Site Scripting (XSS).
🔧 Fix: Stripped ASCII control characters ([\x00-\x1F\x7F]) and replaced string prefix checks with standard WHATWG URL constructor protocol resolution, enforcing http: or https:.
✅ Verification: Ran bun run check and bun run build. Verified that dangerous schemes and obfuscated control characters are reliably rejected.

---

PR created automatically by Jules for task 10567367803435919058 started by @one-more-refactor

[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.

[coderabbitai]

Important

• 🔍 Trigger review

This repository does not receive automatic reviews because it has fewer than 10 stars.

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Team

Run ID: 019b1463-84a4-4df0-b3ef-4f367d81a407

---

Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out.

❤️ Share

• X
• Mastodon
• Reddit
• LinkedIn

_{Comment @coderabbitai help to get the list of available commands.}