I'm marking this as ready for review, but I'm very, very close to splitting this apart into separate PRs as this became a much larger change than initially planned. However, all the changes are linked to the primary change.

I believe the individual commits are properly separated enough that this could be reviewed, but again I'm not against pulling this apart and splitting it into smaller PRs.

There are primarily four changes layered here.

1. Bug fixes in zoneinfo_rs + adding support for designations and is_dst (a bug fix in itself) (296e67b and 18a4ed2)
2. Add a data-inspect tool for viewing the experimental_tzif data provider (3593004)
3. Rebuild the baked data for the compiled time zone provider (971ee6b)
4. Implement the logic for the zerocopy compiled time zone provider

The reason this PR became so large was that the initial goal was to implement 4. However, implementing 4 exposed some bugs in zoneinfo's baked data provider, which prompted 1 (to fix the bugs), 2 (to help identify and diagnose the bugs), and 3 (to fix the bad compiled data with the fixed version).

I probably won't have time to review a change this big, even commit-by-commit, any time soon. So splitting might be better?

Sounds good to me. I'll rework it into smaller PRs.