Upgrade @noble/hashes to v2 in carpincho-wallet

[gabitoesmiapodo]

User story / Problem statement

Currently @noble/hashes is a major behind (1.8.0 vs 2.x) in carpincho-wallet. It is a cryptographic dependency, so the upgrade needs the highest scrutiny of the epic.

Expected outcome

carpincho-wallet uses @noble/hashes 2.x with all crypto call sites verified against the new API.

Acceptance criteria

• @noble/hashes 1.8.0 → 2.x in carpincho-wallet
• Audit every call site for changed API surface and import paths
• Confirm hashing behavior against known test vectors
• Lint + typecheck + tests pass

Technical notes

Part of #76. API and import paths changed between 1.x and 2.x; do not merge without verifying output equivalence.