[contracts] Add SEP-41 compliance test suite that all token contracts must pass

[CelestinaBeing]

Context

Every SEP-41 token in contracts/ should pass a standard compliance test suite. Currently tests are per-contract and not standardized.

Work

• Create contracts/test-support/sep41_compliance.rs with tests for all SEP-41 functions
• The test suite takes a generic contract type and runs all compliance checks
• Apply to all token contracts: deposit-withdraw, flashloan-token, amm-pool LP tokens
• Add to CI as cargo test -p sep41-compliance

Acceptance criteria

• Compliance suite runs against 3+ contracts
• Any SEP-41 function deviation causes test failure
• CI job added

[JClark011]

@JClark011 has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

Hello Maintainer, I’ve reviewed the issue description and I’m confident I can work on it effectively. Please assign it to me.

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[Caneryy]

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

Hello, I'd like to work on this issue.

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[nonso7]

@nonso7 has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

Can i work on this issue

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[drips-wave]

Congratulations, @nonso7! 🎉 Your application was accepted by the repo's maintainers, and the issue is due on June 30, 2026.

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