Add Contributor Reputation System

[Abd-Standard]

Description

Implement a reputation system that rewards contributors based on completed tasks and successful submissions.

Requirements
Store contributor reputation.
Increase score after accepted submissions.
Display reputation in contributor profiles.
Make the system extensible for future badges.

Acceptance Criteria
Reputation updates correctly.
API exposes contributor score.
Frontend displays reputation.

[CodeMayor]

Hi! I'd like to work on this issue. I have experience building full-stack features involving backend APIs, database models, and React/Next.js frontends. I'll implement a contributor reputation system that updates automatically after accepted submissions, expose the reputation through the API, display it on contributor profiles, design the implementation to support future badge functionality, add comprehensive test coverage, and ensure the solution is well-documented and ready for review.

[grantfox-oss]

🦊 GrantFox — @CodeMayor has been assigned to this issue as part of the Official Campaign | FWC26 campaign!

Next steps:

1. Open a Pull Request referencing this issue (e.g., Closes #131)
2. Your PR will be reviewed by the Core-Foundry maintainers

Good luck! Track your progress on GrantFox.