Feature on chain reputation registry contract

[omolobamoyinoluwa-max]

Summary
Implement comprehensive on-chain reputation registry contract using Stellar account data entries to store immutable, queryable reputation data for users on the TaskChain platform.

Problem Statement
TaskChain needed an on-chain reputation system to provide transparent and tamper-proof reputation management for freelancers. The existing database-based reputation system, while functional, lacked the immutability and verification capabilities of blockchain-based storage.

Solution
Implemented an on-chain reputation registry using Stellar's account data entries, providing immediate blockchain storage while preparing for future Soroban smart contract migration. This system stores completion scores, dispute counts, and total contracts participation data on the Stellar blockchain, ensuring reputation data is tamper-proof and verifiable.

Features
Immutable On-Chain Storage: Reputation data stored in Stellar blockchain account data entries
Completion Score Tracking: Weighted calculation (70% previous + 30% new performance) with range 0-100
Dispute Count Tracking: Automatic incrementing with score impact calculation
Total Contracts Tracking: Comprehensive contract participation counting
Queryable Interface: Multiple API endpoints for reputation data retrieval
Automatic Updates: Helper functions for contract completions and dispute recording

Acceptance Criteria ✅
✅ Store completion score for each user (0-100 scale)
✅ Track dispute count per user
✅ Record total contracts participated in
✅ Data stored immutably on-chain
✅ Queryable interface for reputation data retrieval

Testing
lib/tests/blockchain-reputation.test.ts - Comprehensive unit tests covering all acceptance criteria and edge cases
Technical Implementation

Architecture Choice
Current: Stellar account data entries (64-byte limit, immediate availability)
Future: Migration path to Soroban smart contracts (when available in project)
Rationale: Provides immediate on-chain storage without waiting for Soroban infrastructure

Integration Points
Complements existing database-based reputation system
Can be integrated with Stellar payment worker for automatic updates
Provides verification layer for platform reputation data

Testing
Unit Tests: Comprehensive test coverage for all functions
Validation: Input validation and edge case handling

Acceptance Criteria: All acceptance criteria verified through tests
Manual Testing: Instructions provided for manual verification

Security Considerations
Private key management recommendations

Data validation before on-chain updates
Rate limiting recommendations for API endpoints
GDPR compliance considerations

Performance Considerations
Stellar data entry limits (64 bytes) respected
Caching strategies recommended for API endpoints
Monitoring recommendations for key metrics

CI/CD Readiness
Lint: Code follows project's existing ESLint configuration
Build: Integrates seamlessly with existing Next.js and Stellar infrastructure
No Breaking Changes: All additions are new files, no modifications to existing code

Impact
Expected Impact: High - Significantly improves user experience by providing verifiable, on-chain reputation data that builds trust in the TaskChain ecosystem.

Closes #83

[drips-wave]

@omolobamoyinoluwa-max Great news! 🎉 Based on an automated assessment of this PR, the linked Wave issue(s) no longer count against your application limits.

You can now already apply to more issues while waiting for a review of this PR. Keep up the great work! 🚀

Learn more about application limits