fix(stats): restore aggregated language donut

Merged
TR
1d ago
+149-107

Summary

  • Restore the original gradient donut layout for top-langs.svg.
  • Preserve cross-repository language aggregation across trvny and travnie (no forks).
  • Add renderer regression tests and run them from the existing stats workflow.

The checked-in SVG uses the latest displayed rounded percentages. Scheduled stats refresh will regenerate using the exact GitHub language byte counts.