[feature] add audit log

we need an audit log
- date/time, exception if any, code, result, time, was change detected

this would probably help in the future for debugging/adding new plugins/methods too

The issue names no files or tests. Start by tracing the change-detection and plugin/method execution paths, then identify where date/time, exceptions, code, result, duration, and change status could be recorded. Done means the audit log captures the requested fields across the relevant operations and has documented verification.

Written by the indexing model from the issue text.