Add Build Script Reproducibility Verification

[maugauwi-hash]

Labels: enhancement, infrastructure, security
Priority: Medium
Estimated Time: 1.5 hours

Description:
scripts/build.sh produces the WASM artifacts deployed to mainnet, but there's no verification that two independent builds from the same commit produce byte-identical output, which matters for audit trust.

Tasks:

• Pin toolchain versions explicitly in scripts/build.sh
• Add a CI job that builds twice and diffs the resulting WASM hashes
• Fail CI on non-reproducible output
• Document reproducible build steps in docs/deployment-guide.md

[james2177]

@james2177 has applied to work on this issue as part of the Stellar Wave Program's 8th wave.

hello maintainer can i work on this

ℹ️ Repo Maintainers: To accept this application, review their application or assign @james2177 to this issue.

[drips-wave]

Congratulations, @james2177! 🎉 Your application was accepted by the repo's maintainers, and the issue is due on August 31, 2026.

🧑‍💻 @james2177: 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

When opening a PR, please link it to this issue to ensure it gets tracked accurately. Points are awarded when this issue is marked as completed by the maintainer.

🤠 Repo maintainers: Please keep an eye on the contributor's progress and review their work before the due date. You can manage this issue, including adjusting its complexity and points, here.

🌊 Happy Wave 🌊

[grantfox-oss]

🎉 This issue has been marked as completed on GrantFox!

@james2177's PR #454 was approved and merged by @maugauwi-hash.

🏆 @james2177: You earned 35 FoxPoints for this contribution! Your current tier: Explorer (710 total points). Track your full progress on GrantFox.

👏 Great work, @james2177! Keep contributing to ethos-protocol.