Migrate audit log to batched logging system

[HyeockJinKim]

Objective

Migrate audit log creation from direct DB writes to the batched logging system.

Implementation Details

Repository Changes

1. Update AuditLogDBSource
   • Add bulk_create() method using BulkCreator
   • Keep existing create() for backward compatibility

async def bulk_create(
    self, 
    creators: Sequence[Creator[AuditLogRow]]
) -> list[AuditLogData]:
    async with self._db.begin_session() as db_sess:
        result = await execute_bulk_creator(db_sess, BulkCreator(specs=[c.spec for c in creators]))
        return [row.to_dataclass() for row in result.rows]

1. Update AuditLogRepository
   • Route create() calls to queue manager
   • Add flush() method for manual flush operations

Service Changes

1. Update AuditLogService
   • Change create() to enqueue instead of direct DB write
   • Return immediately without waiting for DB write

Integration

• Wire LogQueueManager into AuditLogService
• Configure batch writer for audit logs
• Set Redis backup enabled for audit logs (critical)

Testing

• Test audit log enqueueing
• Test batch creation with multiple entries
• Test flush on interval and threshold
• Integration tests with real DB

Migration Strategy

• Feature flag for gradual rollout
• Monitor queue depth and flush latency
• Rollback plan if issues detected

Acceptance Criteria

• Audit logs written in batches
• No functional regression
• Reduced DB transaction count (target: 90%)
• All tests passing

JIRA Issue: BA-4234