Switch default scoring method from weighted to copeland

[that-github-user]

Summary

Based on the scoring evaluation (docs/scoring-evaluation.md, #105, #106), Copeland should be the default scoring method:

• Copeland and Borda agree 86% (independent validation)
• Weighted disagrees with both ~40% (arbitrary weights distort)
• Copeland is scale-independent and Condorcet-consistent

Change

In src/cli.ts, change the default for --scoring from "weighted" to "copeland".

One line change. Data-driven decision.

[that-github-user]

Fixed in #110. Default scoring switched to Copeland based on empirical evidence from 21 runs (docs/scoring-evaluation.md). Weighted still available via --scoring weighted.