chore: Avoid duplicate N-API Cargo build (#13388)
## Summary
- make the inferred `turborepo-napi#build` task a hash-only dependency
- retain Cargo-derived transitive Rust input hashing without running a
preliminary Cargo build
- let `@turbo/repository#build` perform the specialized N-API build
exactly once
## Testing
- `turbo run build --filter=@turbo/repository --dry`
- `turbo run build --filter=@turbo/repository --log-order=stream`
- `turbo run test --filter=@turbo/repository --log-order=stream` (21
passing)
- pre-push hooks
