The tss.NewParameters() expects the party count to match the number of
parties in peerCtx. For signing, this should be len(sortedPartyIDs)
(actual signing participants), not thresholdN (original keygen parties).
This fixes the "U doesn't equal T" error in round 9 when doing 3-of-5
co-managed signing with parties at indices 2,3,4.
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>