[Refactor] Standardize error handling across services

[Eniola3321]

Labels: refactor, error-handling, priority:medium
Description:
Different services throw errors inconsistently.
Acceptance Criteria:

Create custom exception classes
Use consistent error messages and codes
Update services to use new pattern
Difficulty: intermediate

[omonxooo-commits]

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

'm a full-stack developer and I'd like to take this issue.
I understand the requirements and will follow the existing project structure, keep the implementation clean, and include proper tests where applicable.

ETA: 1–3 days (depending

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

[heymide]

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

Hello, I’ve gone through the requirements and I’m confident I can implement a proper solution that matches the acceptance criteria. Kindly assign this issue to me.

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

[Hakimziyech18]

@Hakimziyech18 has applied to work on this issue as part of the Stellar Wave Program's 5th wave.

Please Maintainer, assign me this issue to resolve, Thank you.

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[thewealthyplace]

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

Hi, I can work on this issue.

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[silhilston]

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

I'd like to work on this.

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[drips-wave]

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

🧑‍💻 @silhilston: 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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