Restructure lock metadata

[blakeNaccarato]

Please use this form appropriately

• [X] I am a maintainer or I have been directed to use this form.

Please check that this internal matter hasn't already been raised

• [X] I searched here or here and couldn't find a similar issue.

Description

Metadata is currently in direct.

• [ ] Separate these into time, compiler, and directs.
• [ ] Drop the sep property of a dependency specification, it can be inferred from the specification (e.g. git+https... has @ sep, etc.)
• [ ] directs should be mappings from dependency names to a version specifier, with environment markers stripped. Compose the set of specifiers from directs AND nodeps.in with uv pip compile ... --no-deps ... --override overrides.txt, then extract the singular versions from that, appending submodule commit revisions as well.
• [ ] Compare the compiler from lock to the current compiler, then the directs, only re-locking if either doesn't match
• [ ] Remaining locks are a mapping from platform identifiers to time and requirements.

[blakeNaccarato]

This is done, though the restructure ended up being a little different. It happened when introducing --universal flag.