chore: prepare barretenberg-rs for crates.io publishing

[johnathan79717]

Summary

• Add include field to barretenberg-rs Cargo.toml so generated api.rs and generated_types.rs are packaged by cargo publish, even though they remain gitignored
• Add release function to barretenberg/rust/bootstrap.sh — sets crate version from REF_NAME, verifies generated files exist, and runs cargo publish
• Hook barretenberg/rust into the top-level release orchestrator (after barretenberg/ts which generates the Rust bindings)
• Add publish = false to the tests crate

How it works

1. Generated files stay gitignored — not committed to the repo
2. The include field in Cargo.toml overrides .gitignore for cargo publish, so the files are packaged as long as they exist on disk
3. During a release, barretenberg/ts runs first (which calls yarn generate), then barretenberg/rust publishes
4. No separate workflow — follows the same unified release flow as npm packages

Test plan

• cargo package --list --allow-dirty confirms src/api.rs and src/generated_types.rs are included
• cargo publish --dry-run --allow-dirty --no-verify succeeds
• Set CARGO_REGISTRY_TOKEN env var in release environment before first publish

[ludamad]

I'm opposed to this. this is how people get messy PR diffs and end up having to ask if they're messing something up

[johnathan79717]

I'm opposed to this. this is how people get messy PR diffs and end up having to ask if they're messing something up

I uncommitted those files.

[johnathan79717]

Backporting this to v4 because we need to publish v4 barretenberg-rs releases for ZKPassport.

[AztecBot]

✅ Successfully backported to backport-to-v4-staging #21064.