Implement a Nix flake for reproducible development environments

[Marvy247]

Create a flake.nix providing: Rust toolchain (with wasm target), Noir (nargo), Node.js, Soroban CLI, and all system dependencies. Enables instant reproducible dev shell.

[zachyo]

@zachyo has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

I would like to work on this

ℹ️ Repo Maintainers: To accept this application, review their application or assign @zachyo to this issue.

[drips-wave]

Congratulations, @zachyo! 🎉 Your application was accepted by the repo's maintainers, and the issue is due on June 30, 2026.

🧑‍💻 @zachyo: Please resolve the issue such that the repo's maintainers have enough time to review your contribution before the due date. You'll earn Points for completing the issue on-time, which will make you eligible for a share of the Stellar Wave Program's reward pool.

Warning

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