[Backend] Implement Scheduled Notification Dispatcher

[Abd-Standard]

Description

Create a dispatcher capable of sending notifications automatically at scheduled times.

Tasks
Store scheduled execution time.
Poll pending schedules.
Dispatch eligible notifications.
Handle missed schedules.

Acceptance Criteria
Notifications are dispatched on schedule.
Missed schedules are handled gracefully.
Scheduler supports retries.

Contributors start work by running:
git checkout -b backend/scheduled-dispatcher

[ekwe7]

I would love to work on this issue. I have experience building production ready applications and collaborating through GitHub workflows. I'll carefully analyze the current implementation, propose a reliable solution, and submit a well-tested PR. My focus is on clean code, maintainability, and timely delivery

[Cerome360]

@Cerome360 has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

I'd love to work on #306. I read through the issue, and I appreciate that it's covering the full lifecycle of scheduled notifications instead of just triggering them at a given time. Looking forward to contributing.

ℹ️ Repo Maintainers: To accept this application, review their application or assign @Cerome360 to this issue.

[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!

[NnamdiCyber]

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

I would like to work on this, Please assign me

ℹ️ Repo Maintainers: To accept this application, review their application or assign @NnamdiCyber 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 #306)
2. Your PR will be reviewed by the Core-Foundry maintainers

Good luck! Track your progress on GrantFox.