refactor(architecture): split wallet/service.go (553 lines) and move crypto out of the service layer

[cypriannwokolo2-creator]

Summary

internal/domain/wallet/service.go (553 lines) mixes wallet creation, Horizon funding/trustline/USDC seeding, signing, payment security checks, and AES-256-GCM encrypt/decrypt helpers.

Acceptance Criteria

• Extract crypto (encrypt/decrypt/key-derivation) into a dedicated package
• Extract Stellar funding/trustline operations into pkg/stellar helpers
• Service focuses on orchestration + security policy
• No behavioral change; tests added/kept green

Complexity

High.

[supreme2580]

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[Gentleslyl2006]

@Gentleslyl2006 has applied to work on this issue as part of the Stellar Wave Program's 8th wave.

Hello maintainer
If this issue get assigned to me. You're guaranteed perfect results in return. I can fix it

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[FICKSONPRO]

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

Hi Maintainer, I went through the issue in detail and I'm clear on the root cause as well as the expected behavior outlined in the acceptance criteria. I have experience working on similar issues, so I can move quickly while keeping the fix scoped and easy to review. I'd be glad to take this on and can start right away  happy to share more about my approach if that's helpful

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[Alagba467]

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Hi maintainer I would like to work on this issue, thank you.

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[Chinonso-Peter]

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

Can i work on this issue

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[drips-wave]

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

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