`stealth-batch-sender` Soroban contract

[truthixify]

Tier: L (1-2 weeks) Type: feature

Context

EVM WraithSender already supports batchSendETH and batchSendERC20. Stellar has stealth-sender for single transfers and stealth-splitter for proportional 1:N distribution, but no equivalent for the simple "send to N pre-computed stealth addresses in one transaction" use case.

Scope

• New crate contracts/stellar/stealth-batch-sender/
• batch_send(from, transfers: Vec<Transfer>, asset) entrypoint where each Transfer carries the pre-computed stealth address, ephemeral pub key, and amount
• All-or-nothing semantics via Soroban transaction model
• Per-transfer announcement emission
• Cap batch size (justify against Soroban resource budget)
• Tests: success, atomicity-on-mid-batch-failure, max-size, validation

Acceptance criteria

• New crate compiles and passes its own tests
• Property test for atomicity guarantee
• Resource-budget comparison vs. N individual stealth-sender::send calls
• SDK follow-up issue filed for buildBatchSendStellar builder
• Demo follow-up issue filed for batch-send UI

Files to start with

• contracts/stellar/stealth-sender/src/lib.rs (single-send reference)
• contracts/stellar/stealth-splitter/src/lib.rs (atomic distribution reference)
• contracts/evm/contracts/WraithSender.sol::batchSendETH (parity)

[cokehill]

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

Hi, I'd like to work on this. I'm a Rust developer with experience building production systems — happy to discuss approach before opening a PR if needed.

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

[drips-wave]

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

🧑‍💻 @cokehill: 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.

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[truthixify]

@cokehill Assigned. Welcome to wave 6.

Quick expectations to make this smooth for both sides:

1. Branch from develop (not main). PRs target develop.
2. Open a draft PR within ~3 days of pickup so we can see direction early.
3. Update at least every 5 days. If you get stuck or context changes, just say so on the PR — silence is the only thing that costs you the assignment.
4. Read the issue body's acceptance criteria carefully. Hitting those is the merge bar.

If anything is ambiguous, ask before building. Looking forward to the PR.

[truthixify]

Resolved by #79 (merged into develop).

[drips-wave]

This issue has been completed by @cokehill as part of the Stellar Wave Program's 6th Wave 🥳

😎 @cokehill: You earned 200 Points for completing this issue! After the current Wave ends, you'll be eligible for a percentage of the Wave's reward pool based on the percentage of total points you've earned. Learn more here. You can also Leave a review to share your experience working on this issue.

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