chore: make repometadata struct public

[JoeWang1127]

Make LibraryInfo and its field public. This struct will be used in repo metadata generation in Go clients.

For #3617

[gemini-code-assist]

Code Review

This pull request makes the LibraryInfo struct and its fields public to be used in other packages. The change is straightforward. My main feedback is to add documentation comments for the newly exported struct and its fields, as required by the repository's Go style guide.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 82.01%. Comparing base (c3fe4ef) to head (41bb146).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #4056   +/-   ##
=======================================
  Coverage   82.01%   82.01%           
=======================================
  Files          77       77           
  Lines        6504     6504           
=======================================
  Hits         5334     5334           
  Misses        825      825           
  Partials      345      345           

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.