Addition of pub(crate) visibility and other formatting updates

[vivek-arte]

This PR makes further updates to the Rust test vectors to make it possible to copy paste the vectors directly into the places they are used.

It adds the pub (crate) visibility to the test vector struct and adjusts the indentation of the vectors to match usage in the repositories.

[oxarbitrage]

The changes to tv_rust() in output.py look good. Verified that running bash regenerate.sh rust all with the PR's output.py produces the files committed in this PR. Also confirmed the generated files compile correctly as Rust modules with the expected pub(crate) visibility and indentation.

The two additional changes are minor:

• zcash_test_vectors/orchard/note.py: removes an unused Scalar import.
• pyproject.toml: alphabetical reordering of two script entries.

Merge order note: This PR should be merged before #112, since #112's rustfmt pass should be applied on top of these generator changes. Once this is merged, #112 will need to be rebased.

[oxarbitrage]

@vivek-arte can you rebase this onto main? PR #115 (Poetry → uv migration) landed since your last push, and I want to make sure CI passes with the new build system before merging. Once this is in, we can rebase and merge #112.

[vivek-arte]

@oxarbitrage I rebased it, the CI works successfully on our local PR (QED-it#42) but the run needs to be approved on this repository.