🔒 Prevent path traversal in process commands

[Tcode-Motion]

🎯 What: Added validation to prevent path traversal (..) and null bytes (\0) in command execution via std.process.run and std.process.spawn.
⚠️ Risk: Arbitrary command execution could be leveraged using path traversal sequences to execute unauthorized binaries outside intended directories, even if the Process capability is restricted to specific paths.
🛡️ Solution: Implemented checks in both run and spawn callbacks to explicitly reject commands containing .. or \0, ensuring only safe, direct commands or explicit absolute paths (without traversal) can be executed.

---

PR created automatically by Jules for task 3065281696807958351 started by @Tcode-Motion

[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.