[Backend] -- Implement User Activity Timeline

[Devsol-01]

Description:
Create comprehensive user activity timeline showing all actions (savings, deposits, withdrawals, votes, referrals) with filtering and search.

Acceptance Criteria:

• Design activity timeline schema
• Implement activity tracking service
• Create timeline API endpoints
• Add activity type filtering
• Implement date range filtering
• Add pagination and sorting
• Create activity search

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[RaymondAbiola]

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

Hi, I’d like to work on this issue. I have experience with rust, Solidity, frontend, and backend development, and I’m confident I can deliver a clean solution.

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

[favvy0217]

@favvy0217 has applied to work on this issue as part of the Stellar Wave Program's 5th wave.

i would love to work on this issue

ℹ️ Repo Maintainers: To accept this application, review their application or assign @favvy0217 to this issue.

[drips-wave]

Congratulations, @favvy0217! 🎉 Your application was accepted by the repo's maintainers, and the issue is due on June 2, 2026.

🧑‍💻 @favvy0217: 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

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