chore(dev): codebase setup for issue #2395

[luisortz]

This PR prepares the repository for working on issue #2395 (vector index initialization / backfill).

Changes

• Added Dockerfile for reproducible development and testing environment.
• Fixed loki_logger_handler import to support updated LoggerFormatter name.
• Verified that vector-related tests run successfully inside the container.

Validation

Reproduce locally:

docker build -t superduper-dev .
docker run -it --rm -v "$PWD:/app" superduper-dev bash
pip install -e plugins/mongodb
pytest -q test -k "vector"   # 59 passed, 670 deselected