MVP: Structured verdict logging schema

[kuyacarlo]

Parent: #74

Scope

Define and implement JSON log shape: action, verdict, repo, timestamp, policyId, validation_id, rule_id.

Files

• backend/app/core/logging.py
• backend/app/services/logger.py
• Document in README / docs/mvp

Related

#4

DoD

• Schema documented
• Logger emits required keys for allow/block/HITL outcomes