Add cross-contract token transfer failure handling tests asserting TransferFailed and no partial state

[thlpkee20-wq]

Description

RevoraError::TransferFailed covers cross-contract token transfer failures during payout/deposit flows. The contract must not leave partial state (e.g. marking a period claimed, mutating balances) when the underlying token transfer reverts. Extend the cross-contract failure suite to assert atomicity and the typed error on a failing token.

Requirements and context

• Must be secure, tested, and documented
• Should be efficient and easy to review
• Relevant code: src/lib.rs (deposit_revenue, claim flow, TransferFailed), src/test_cross_contract_transfer_fail.rs
• Use a mock token that fails transfer to assert rollback

Suggested execution

• Fork the repo and create a branch
• git checkout -b feat/transfer-failure-atomicity-tests
• Implement changes
  • Deploy a token stub whose transfer panics/fails
  • Invoke deposit/claim and assert TransferFailed (via try_*)
  • Assert claimed flags and audit state are unchanged after failure
• Validate security and correctness assumptions

Test and commit

• Run tests
  • cargo test
• Cover edge cases
  • Failure on first deposit, failure mid claim loop, retry after failure
• Include test output and security notes

Example commit message

test: assert atomic rollback on cross-contract transfer failure

Guidelines

• Minimum 95 percent test coverage
• Clear documentation
• Timeframe: 96 hours

[Abdulmajeed82]

@Abdulmajeed82 has applied to work on this issue as part of the Stellar Wave Program's 5th wave.

I would like to work on this issue pls..

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[drips-wave]

Congratulations, @Abdulmajeed82! 🎉 Your application was accepted by the repo's maintainers, and the issue is due on June 2, 2026.

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