Implement LogCleaner cron job to automatically clean up old log records
based on configurable retention period and maximum record count.
- Add LogCleaner with retention_days and max_records configuration
- Add EZ_LOG_RETENTION_DAYS and EZ_LOG_MAX_RECORDS environment variables
- Default to 30 days retention and 1,000,000 max records
- Include unit tests for log cleaner functionality
