Uv for package management

[wrgeorge1983]

everything from #211 PLUS:

migrate to uv:

• genuine lockfile that ensures (by hash) dependencies are held constant forever until deliberately updated
• faster builds and syncs
• pyproject.toml for more standard project description and dependency mgmt. On the road to pip-installable.

multi-stage dockerfiles

• smaller docker images (760MB vs 960MB)

also update main docker-compose.yml to reduce unnecessary rebuilds

fewer dockerfiles

[tbotnz]

@wrgeorge1983 is this ready to merge?

[wrgeorge1983]

@tbotnz yep! I tested by docker compose up --build after purging images etc. you might want to do the same to dbl check since the CI seems broken