Data streaming: write journals

### Acceptance criteria
- Python or rust process implemented as a standalone python package (e.g. see packaging for `ibex_bluesky_core`/`genie`/`lewis` for how to do this) or rust project
* e.g. named `kafka_dae_journals`, to sit alongside `kafka_dae_control` and `kafka_dae_diagnostics`
- Listens to a kafka stream for run stop messages
- Update a `journal.xml` file with metadata from the run when a [`wrdn`](https://github.com/ess-dmsc/streaming-data-types/blob/master/schemas/wrdn_finished_writing.fbs) is published - this then needs to read the file and pull out the journal metadata.
- Format of written `journal.xml` should match existing `journal.xml` as closely as possible.
- Create a follow up ticket to test against Journal Viewer (currently some missing data)

### Notes
- Some metadata won't currently be available from kafka. Create new ticket(s) for these cases. For this ticket, write the data which is _currently_ available from kafka run start/stop messages and corresponds to a field in the `journal.xml`. Create follow up ticket(s) for data not currently available.

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Discussed Planning 08/01/2026 14:30