Omit wheels from lockfile based on `--exclude-newer` (#12299)
## Summary
We respect `--exclude-newer` during resolution, but we weren't applying
it to individual _files_ when writing the lockfile. As a result, if
wheels were added to a distribution after its initial release, we'd end
up including them in the lockfile, even if they were uploaded after the
`--exclude-newer` date.
Closes https://github.com/astral-sh/uv/issues/12296.
