Add Gemini computer use support

[MagellaX]

Summary

• wrap the side panel service worker fetch calls so Gemini computer-use requests always include the browser computer_use tool
• load the wrapper ahead of the existing worker to keep behavior unchanged otherwise
• expose the Gemini computer-use model in settings data with a requires_computer_use flag

(#148)

[github-actions]

CLA Assistant Lite bot ✅ All contributors have signed the CLA. Thank you for helping make BrowserOS better!
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[MagellaX]

I have read the CLA Document and I hereby sign the CLA

[MagellaX]

any thoughts @shadowfax92 ??

also i wanted to join as a intern, so wanted to talk!