Switch default scoring from weighted to copeland (#110)

Data-driven decision based on scoring evaluation (docs/scoring-evaluation.md):
- Copeland and Borda agree 86% (independent validation from social choice theory)
- Weighted disagrees with both ~40% (arbitrary point weights distort)
- Copeland is scale-independent and Condorcet-consistent

Closes #109

Co-authored-by: unknown <that-github-user@github.com>
Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: 3 people

src/cli.ts

@@ -43,7 +43,7 @@ program
     "Convergence clustering similarity threshold (0.0-1.0)",
     String(cfg.threshold),
   )
-  .option("--scoring <method>", "Scoring method: weighted (default) or copeland", "weighted")
+  .option("--scoring <method>", "Scoring method: copeland (default) or weighted", "copeland")
   .option("--verbose", "Show detailed output from each agent")
   .action(async (promptArg: string | undefined, opts) => {
     const prompt = resolvePrompt(promptArg, opts.file);