Improve hand tracking through screen landmarks

[DanielBelmes]

I did try using the wrist to thumb vector to detect hand orientation more fine grain. Apparently media pipe does a killer job with the vector positions and the plane used in hand tracking has a perfectly good normal.

Fixed a bug I was seeing causing the capture page to crash in the capture pages header.

Summary

🤖 Generated by Copilot at 3329a56

This pull request fixes a bug in the hand pose alignment for motion capture and adds a safety check for the user avatar details in the UI. It modifies solveMotionCapturePose.ts and Header/index.tsx in the engine and ui packages respectively.

References

closes #insert number here

Explanation

🤖 Generated by Copilot at 3329a56

• Fix hand pose alignment bug by using screen coordinates instead of original landmarks in solveHand calls (link, link) in solveMotionCapturePose.ts

🤖 Generated by Copilot at 3329a56

Oh we're the coders of the sea, we write the code that makes it be
We fix the bugs and add the features, we make the UI look so neat
We use the ?. operator, to avoid the errors that might occur
And we align the hand pose right, with screenlandmarks in our sight

QA Steps

List any additional steps required to QA the changes of this PR, as well as any supplemental images or videos.

Checklist

• If this PR is still a WIP, convert to a draft
• When this PR is ready, mark it as "Ready for review"
• ensure all checks pass
• Changes have been manually QA'd
• Changes reviewed by at least 2 approved reviewers