refactor(internal/repometadata): use library to generate metadata

[JoeWang1127]

Refactor library struct as one of the inputs to generate metadata from API.

In Go clients, some metadata, e.g., documentation url and distribution name, requires Go specific configuration from the library.

This is a preparation step for Go metadata generation.

For #3617

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 81.92%. Comparing base (d54fc6a) to head (b23bb47).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4068      +/-   ##
==========================================
- Coverage   81.93%   81.92%   -0.01%     
==========================================
  Files          78       78              
  Lines        6516     6513       -3     
==========================================
- Hits         5339     5336       -3     
  Misses        832      832              
  Partials      345      345              

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[gemini-code-assist]

Code Review

This pull request is a good refactoring that simplifies the metadata generation logic. By removing the intermediate LibraryInfo struct and passing the config.Library struct directly, the code becomes cleaner and more maintainable. The change to initialize RepoMetadata using a single, alphabetically sorted struct literal in FromAPI also significantly improves readability. This is a solid preparatory change that I approve.