Replaces the Phase-2 stub with a real impl. Mode "delete" issues a bulk
payload.delete with overrideAccess:true to bypass the append-only rule.
Mode "pseudonymize" fetches up to 10_000 matching docs and patches each
actorId to the token produced by pseudonymize(). Adds 3 eraseSubject unit
tests to the existing payload-audit-log test file.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Adds `pseudonymize(actorId)` in core-audit — SHA-256 of salt+":"+actorId
truncated to 16 hex chars, prefixed "erased-". Salt from
AUDIT_PSEUDONYM_SALT env (fallback dev label). 6 unit tests: deterministic,
salt-change-differs, fallback-no-throw.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
