#473: omit empty releases cursor

[akmhatey-ai]

Closes #473.

What changed:

• Applies the same conditional after interpolation used by adjacent GraphQL methods to total_releases_published.
• Adds a regression test that captures the first releases query and verifies it no longer sends after: empty string when the cursor is nil.

Validation:

• Red before the production change: bundle exec ruby test\fbe\test_github_graph.rb -- --no-cov failed on test_total_releases_published_omits_after_when_cursor_is_nil because the query contained after: empty string.
• Green after the production change: bundle exec ruby test\fbe\test_github_graph.rb -- --no-cov passed with 23 tests, 48 assertions, 0 failures, 0 errors, 6 skips.
• bundle exec rubocop lib\fbe\github_graph.rb test\fbe\test_github_graph.rb
• ruby -c lib\fbe\github_graph.rb
• ruby -c test\fbe\test_github_graph.rb
• git diff --check
• git diff -- lib\fbe\github_graph.rb test\fbe\test_github_graph.rb | gitleaks stdin --no-banner --redact

Limitations:

• I also tried bundle exec rake test locally on Windows. It is blocked before the full suite completes by the existing typhoeus/ethon libcurl loading issue while requiring test_enter.rb, so I am not claiming a local full-suite pass.

[GHX5T-SOL]

Verified the cursor handling change for #473. The first releases page now omits the after: argument instead of sending after: "", and the regression covers that first-page query shape.

Validation:

• env BUNDLE_PATH=/private/tmp/bundle-fbe-488 mise x ruby@3.3.11 -- bundle check -> dependencies satisfied
• env BUNDLE_PATH=/private/tmp/bundle-fbe-488 mise x ruby@3.3.11 -- bundle exec ruby -Itest test/fbe/test_github_graph.rb -- --no-cov -> 23 tests, 48 assertions, 0 failures, 0 errors, 6 skips
• env BUNDLE_PATH=/private/tmp/bundle-fbe-488 mise x ruby@3.3.11 -- bundle exec rake test -> 284 tests, 804 assertions, 0 failures, 0 errors, 9 skips
• env BUNDLE_PATH=/private/tmp/bundle-fbe-488 mise x ruby@3.3.11 -- bundle exec rubocop lib/fbe/github_graph.rb test/fbe/test_github_graph.rb --format simple -> 2 files inspected, no offenses
• ruby -c lib/fbe/github_graph.rb and ruby -c test/fbe/test_github_graph.rb -> Syntax OK
• git diff --check origin/master...HEAD -> passed
• git diff origin/master...HEAD | gitleaks stdin --no-banner --redact --exit-code 1 -> no leaks found

Live pre-review state: open, non-draft, mergeable/CLEAN, all GitHub checks green, no existing comments/reviews. Same-scope open PR search for #473 returned only this PR.

[0crat]

@GHX5T-SOL Great work on the review! 🎉 You've earned +6 points (+18 base, -8 for missing comments, -4 for limited code coverage with 16 hits). Your total score is now +156 - keep up the momentum and check your Zerocracy account for updates!

[yegor256]

@akmhatey-ai merge conflicts here

[yegor256]

Please fix the merge conflicts so this pull request can be merged.