chore: apply black formatting to codebase

## Problem
12 files are not formatted according to black standards.

## Solution
Run black formatter across the codebase:

black src/

## Files affected
- src/python/lib/rmtc/interface.py
- src/python/lib/rmtc/infer.py
- src/python/lib/rmtc/train.py
- src/python/lib/rmtc/artifacts.py
- src/python/lib/rmtc/track.py
- src/python/lib/rmtc_core/io/filesystem/folders.py
- src/python/lib/rmtc_core/artifacts/filesystem/datasets.py
- src/python/lib/rmtc_core/gui/common/widgets.py
- src/python/lib/rmtc_core/gui/common/properties.py
- src/python/lib/rmtc_core/gui/signalbox/widgets.py
- src/python/lib/rmtc_core/train/torch/trainers.py
- src/python/lib/rmtc_core/track/cypher/connection.py

Start by running `black src/` and review the 12 listed Python files under `src/python/`. Done means Black completes successfully and those files are formatted according to Black standards, with no unrelated changes.

Written by the indexing model from the issue text.