Create API Client Method to Request Trustline XDR

[codeZe-us]

Before a user can receive or save USDC, a sponsored USDC trustline transaction must be requested from the backend. The client needs an API method to call this endpoint and retrieve the unsigned trustline activation XDR.

Implementation guidelines:

• Add a repository method requestTrustlineXdr(String accountId) inside SavingsRepository.
• Send a POST request to /api/savings/trustline with the account public key.
• Return the unsigned transaction envelope XDR string to the caller for signing.

Files location: savings_repository.dart

Expected result: The repository retrieves the unsigned trustline transaction XDR from the server API, enabling the wallet UI to initiate local signing.

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[Omolola-art]

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

Hello Maintainer, Please I would like to work on this issue

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[akinz384]

@akinz384 has applied to work on this issue as part of the Stellar Wave Program's 8th wave.

Hi Maintainer i would like to work on this issue

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[harmondconsultant-png]

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

I’d be happy to take ownership of this issue. I’ve reviewed the scope and have a clear understanding of what needs to be done. I can start immediately, follow the existing code patterns, and make sure the changes are properly tested before opening the PR.

I’ll keep the implementation focused and the PR clean and easy to review. I’m happy to take this from implementation through review and address any feedback along the way.

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