fix: hide Omar Metwally from alumni

[chengjiahao1234]

Type of Change

• ✅ Content Update (news, publications, team)

Summary

Commented out Omar Metwally's alumni record so he is no longer displayed on the team page while retaining his information for future reference.

Changes Made

• Commented out Omar Metwally's complete record in _data/alumni_members.yml.
• Retained his position and profile links in the source file.
• Confirmed that Omar no longer appears in the rendered alumni list.

Testing Checklist

• Changes display correctly on desktop (1920x1080 or similar)
• Changes display correctly on tablet (768x1024 or similar)
• Changes display correctly on mobile (375x667 or similar)
• Tested in light theme
• Tested in dark theme
• No broken links or images
• No console errors
• Ran bundle exec jekyll serve locally without errors

Screenshots (if applicable)

Not applicable; this update removes an alumni entry from display.

Related Issues

None.

Additional Notes

• Omar's information was commented out rather than deleted.
• _data/alumni_members.yml parses successfully.
• The production Jekyll build completed successfully.
• The local /team/ page returned HTTP 200 and did not contain Omar's name.

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By submitting this PR, I confirm:

• I have tested these changes locally
• I have followed the code standards in DEVELOPMENT.md
• I have updated documentation if needed
• I am ready for this to be reviewed and merged