bark: Prevent accidental nonce reuse on failing round

Steven Rooserequested to merge
feat/do-not-use-dangerous-sec-nonce into master

Summary by CodeRabbit

  • Bug Fixes

    • Prevents accidental reuse of MuSig2 secret nonces after restarts; signing attempts now fail if required nonces are unavailable.

  • Improvements

    • Secret nonces are kept only in-process to avoid persisting sensitive material.
    • Signing submissions are performed sequentially for increased robustness.
    • Preserves compatibility with existing persisted records.

  • Tests & Docs

    • Added unit tests and updated changelog and test comments.
Edited by coderabbit

Merge request reports