test: add escrow provider + query verification tests

frost-escrow-provider.test.ts (21 steps):
  buildFrostP2PKOptions, verify, verifyLock (P2PK parse, pubkey checks),
  cancel, createHold null without resolver

cashu-escrow-provider.test.ts (20 steps):
  verify (amount checks), verifyLock (HTLC hash+worker parse,
  prefix handling, mismatch detection), cancel, createHold

query-verification.test.ts (19 steps):
  Single oracle pass/fail, CTF-1 oracle ID bypass prevention,
  multi-oracle quorum (threshold met/unmet, aggregation,
  attestation records, independent verification)

254 CI tests / 915 steps passing.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: motxx