fix(d2): datetime.now(UTC) everywhere + SQLITE-001 automation tests on ephemeral postgres

app/routes/audit.py

@@ -6,7 +6,7 @@ import csv
 import io
 import json
 import uuid
-from datetime import datetime, timedelta
+from datetime import UTC, datetime, timedelta
 
 from fastapi import APIRouter, Depends, HTTPException, Query
 from fastapi.responses import StreamingResponse
@@ -167,7 +167,7 @@ async def audit_retention_cleanup(
     Default retention: 365 days.
     """
     tenant_id = uuid.UUID(current_user["tenant_id"])
-    cutoff = datetime.utcnow() - timedelta(days=retention_days)
+    cutoff = datetime.now(UTC) - timedelta(days=retention_days)
 
     q = delete(AuditLog).where(
         AuditLog.tenant_id == tenant_id,