uv lock to use overrides from tool.uv (#4108)

[idlsoft]

Summary

This will make uv lock read override-dependencies from the [tool.uv] section of pyproject.toml.
Resolves #4108

Alternative to #4369, an implementation more consistent with pip compile and pip install.

Test Plan

Unit test

[charliermarsh]

I find it a bit strange that overrides are read as configuration (via the settings schema) rather than as part of the pyproject.toml itself, i.e., part of the workspace data (similar to, like, tool.uv.dev-dependencies). I guess this is necessary to respect these overrides in the pip API in addition to uv lock etc.?

[charliermarsh]

I feel like the approach in #4369 is, perhaps, more correct (but only reading from the workspace root)? What do you think @konstin - which approach is more natural to you? Here we're reading the overrides as settings, but we then have the workspace root available to us in uv lock.

[charliermarsh]

Closing in favor of #4369. Thank you!