fix: prevent page scroll when restoring focus on modal close

[pradel]

Summary

Fixes #515.

When a modal is closed, FocusTrap restores focus to the element that was focused before the modal opened using .focus(). Chrome and Safari scroll that element into view, so the page jumps to a "specific scroll distance from the top" (the trigger position) on close — exactly what the issue describes.

This restores the focus with { preventScroll: true }, so focus is still returned to the trigger without moving the page scroll position.

Tests

• Added a unit test asserting focus is restored with { preventScroll: true }
• Added a Cypress e2e test asserting the page scroll position is preserved when the modal is closed

Both tests fail without the fix. Verified vp check, unit tests (59) and Cypress specs (14) pass with the fix.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 83.66%. Comparing base (b69f310) to head (89b6f87).
⚠️ Report is 1 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #578      +/-   ##
==========================================
+ Coverage   80.69%   83.66%   +2.97%     
==========================================
  Files           7        7              
  Lines         202      202              
  Branches       74       74              
==========================================
+ Hits          163      169       +6     
+ Misses         29       24       -5     
+ Partials       10        9       -1     

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