audit log inside mediabus

it would be great to create an "audit" log in mediabus that keep track of "ingest" and "reuse" activity.
this will allow us to easily keep track of what's ingested and used, and probably also facility garbage collection.
exposing this log via admin could allow for innovative asset management applications on top.

i could envision a pseudo log that looks like this:

```
2025-07-31T12:01:21.000 ingest 13872adbc8f226c65c00a81078b84ab4152476fc7 image/png uncled@adobe.com /docs/faq original-filename.png gdoc-preview
2025-07-31T12:01:22.000 re-use 13872adbc8f226c65c00a81078b84ab4152476fc7 image/png tripod@adobe.com /drafts/tripod/docs/faq original-filename.png gdoc-preview
```

including fields such as:
```
timestamp
operation (ingest, reuse)
media hash
content type
user (triggering the operation)
path (where preview was triggered)
original filename (if applicable, eg. in word)
content-source-type
```