Add automated lower-bound testing for dependencies

[rg936672]

What's the issue?

Depends on #807. Automatically run the unit tests with uv's lowest resolution strategy, to ensure that the lower bounds are correct (and remain that way). Note that this will probably require a good bit of fiddling with manual constraints of transitive dependencies, since many Python package don't specify lower bounds on their dependencies - even major packages like PyTorch!

Estimate: Not very difficult but tedious to find a good set of versions.