Refactor error handling to use Result type pattern instead of exceptions

[Smartdevs17]

Description

Services throw exceptions for expected error cases, making error handling unpredictable. Refactor to use Result/Option types for explicit error handling.

Acceptance Criteria

• Result<T, E> type defined with proper TypeScript typing
• All service methods return Result types
• Controllers map Result to HTTP responses
• Exception handling only for unexpected errors
• Migration guide for existing code

Technical Scope

• packages/types/src/exports.ts
• backend/src/services/
• Edge: async Result handling, error type hierarchy, interop with third-party libraries

[Ajibose]

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

I would love to work on this

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[ajulaybeeb]

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

Hi Maintainer
I would like to hop on this issue

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[OkeyAmy]

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

Hello Chief, I would like to work on this issue. I have 3 years of experience as an open source contributor

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[drips-wave]

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

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