🧪 [testing improvement] Add test for uuid module registration

[Tcode-Motion]

🎯 What: The std.uuid module in stdlib/src/uuid.rs was missing a test for its registration logic and uuid_v4 exported function in stdlib/tests/stdlib_tests.rs.
📊 Coverage: The new test_uuid_module function verifies that std.uuid is registered in StdlibRegistry and that uuid_v4 executes without panicking and returns a valid UUID string format containing a dash.
✨ Result: Test coverage improved for the techscript_stdlib crate and std.uuid is guarded against regressions.

---

PR created automatically by Jules for task 616644080963781957 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.