fix(security): address review findings for audit logging

benchmarks/security_audit_bench.py

@@ -16,6 +16,9 @@ from cleveragents.config.settings import Settings
 from cleveragents.infrastructure.database.models import AuditLogModel, Base
 
 
+from cleveragents.application.services.audit_service import _TIMESTAMP_FMT
+
+
 def _make_service() -> AuditService:
     """Create a service backed by in-memory SQLite."""
     Settings._instance = None
@@ -109,16 +112,22 @@ class TimeQueryEntries:
 
 
 class TimePrune:
-    """Benchmark pruning old audit entries."""
+    """Benchmark pruning old audit entries.
+
+    Uses ``setup`` to re-seed 200 backdated entries before *each*
+    benchmark iteration so that every call to ``prune()`` actually
+    deletes rows (ASV calls ``time_*`` multiple times per ``setup``
+    by default).
+    """
 
     timeout = 30
+    # ASV calls setup() before each iteration when number=1.
+    number = 1
 
     def setup(self) -> None:
         self.service = _make_service()
         # Insert entries backdated to 60 days ago
-        old_time = (datetime.now(tz=UTC) - timedelta(days=60)).strftime(
-            "%Y-%m-%dT%H:%M:%S.%f"
-        )
+        old_time = (datetime.now(tz=UTC) - timedelta(days=60)).strftime(_TIMESTAMP_FMT)
         for i in range(200):
             row = AuditLogModel(
                 event_type="plan_applied",