🛡️ Sentinel: [HIGH] Fix unsafe path handling

[acebytes]

🚨 Severity: HIGH
💡 Vulnerability: High-level file reading APIs operated on string paths and followed symlinks by default, creating a TOCTOU (Time-Of-Check Time-Of-Use) window where unintended files could be accessed.
🎯 Impact: Allowed potential access or operations on unintended files if an attacker swapped the target file for a symlink during file reading.
🔧 Fix: Replaced string-based file reading APIs with POSIX open() and O_NOFOLLOW | O_CLOEXEC flags to atomically open the file and securely refuse symlink traversal.
✅ Verification: Run swift test to verify functionality.

---

PR created automatically by Jules for task 10335234877444593855 started by @acebytes

[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.