Broken author links removed from direct-push stories
Gitpulse now renders direct-push bylines as plain text instead of broken links. Committer display names like "Nathan Zylbersztejn" were being turned into GitHub URLs that 404 — the fix removes the URL construction entirely.
Gitpulse was generating broken GitHub links for direct-push commits. When a commit had no associated pull request, the code fell back to constructing a URL from the git committer name — turns out "Nathan Zylbersztejn" is not a valid GitHub handle. The resulting links returned 404s.
The fix removes the faulty URL construction. Direct-push bylines now render as plain text when no verified GitHub login is available, and the existing StoryCard fallback handles this gracefully. PR-merge stories are unaffected — they continue to link to author pages using GraphQL-verified URLs.
This plays into Issue #1's broader goal: story cards should only link to verified sources.