Audit Logging - Medera

Medera writes immutable audit events on:

Source	Table	Migration
PHI access	`phi_audit_logs`	080+
Workflow execution	`agent_workflow_executions.execution_trace[]`	110
Deployment actions	`deployment_audit_log` (WORM)	140 / 145
Config access	Config access audit table	137
Auth events	`auditLogger` + observability platform	—
Realtime corrections	`transcription_corrections`, `clinical_ai_suggestions`	126

WORM semantics

deployment_audit_log is append-only — UPDATE and DELETE are blocked. fixed the actor FK to SET NULL so the WORM invariant holds when an actor is deleted.

Merkle integrity

introduced audit integrity checkpoints — events are chained into a Merkle tree so tampering breaks the chain. Verify via: ``` GET /api/audit/integrity-checkpoints

## Retention

Default 6 years, configurable up to 22 years.

## Reading audit logs ```

GET /api/audit/access-logs
POST /api/audit/exports # signed URL export