[Docs] Create Notification API Error Reference

[Abd-Standard]

Description

Document all API error responses, their meanings, possible causes, and recommended resolutions.

Tasks
List HTTP status codes.
Explain each error response.
Include sample payloads.
Add troubleshooting recommendations.

Acceptance Criteria
Error responses are fully documented.
Examples match the implementation.
Documentation is linked from the API guide.

Contributors start work by running:
git checkout -b docs/api-error-reference

[Menjay7]

Hi! I’m a full-stack developer with a strong blockchain background. I’d love to handle this issue and can deliver a clean, reliable solution. Kindly assign it to me.

[jaynomyaro]

Hi! I came across this issue and would love to work on it. I have experience with similar tasks and I'm confident I can investigate, implement a clean solution, and thoroughly test it before submitting a PR. If the issue is still open, I would appreciate it if you could assign it to me. Thank you!

[emynogithub]

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

Job is done , just the opportunity

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

[1sraeliteX]

@1sraeliteX has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

GM maintainer, I would like to work on this issue, thanks.

ℹ️ Repo Maintainers: To accept this application, review their application or assign @1sraeliteX to this issue.

[Naomi-Gift]

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

Hi. I have reviewed this issue and would like to work on it.

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

[drips-wave]

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

🧑‍💻 @Naomi-Gift: 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.

Warning

When opening a PR, please link it to this issue to ensure it gets tracked accurately. Points are awarded when this issue is marked as completed by the maintainer.

🤠 Repo maintainers: Please keep an eye on the contributor's progress and review their work before the due date. You can manage this issue, including adjusting its complexity and points, here.

🌊 Happy Wave 🌊

[grantfox-oss]

🦊 GrantFox — @Naomi-Gift has been assigned to this issue as part of the Official Campaign campaign!

Next steps:

1. Open a Pull Request referencing this issue (e.g., Closes #303)
2. Your PR will be reviewed by the Core-Foundry maintainers

Good luck! Track your progress on GrantFox.