bug: 3 repos fail nightly — missing generated_contracts.rs build artifact

[noahgift]

Summary

alimentar, trueno-rag, and simular have mod generated_contracts; in their lib.rs but src/generated_contracts.rs is in .gitignore (build artifact). No build.rs or mechanism generates this file in CI.

Error

error[E0583]: file not found for module `generated_contracts`
  --> src/lib.rs:61:1
   | mod generated_contracts;

Five-Whys

1. Why fail? — rustc can't find generated_contracts.rs
2. Why missing? — It's a build artifact in .gitignore, not committed
3. Why no build.rs? — The file is generated by provable-contracts integration tooling, which isn't available in the nightly CI environment
4. Why isn't it available? — Nightly runs on GitHub-hosted runners without the provable-contracts repo or pv tool
5. Why wasn't this caught? — The mod declaration was added (April 2) after nightly workflows were set up

Fix Options

1. Commit a minimal stub generated_contracts.rs to each repo
2. Make mod generated_contracts; conditional with #[cfg(feature = "contracts")]
3. Add a build.rs that generates a stub when the contracts aren't available

Affected: alimentar, trueno-rag, simular