feat: add settlement Controller Settlement Management APIs

[Olowodarey]

This PR implements the SettlementController and related services to manage and track fiat settlements to merchants, addressing issue #34.

Changes

• Settlement Module:
  • Implemented SettlementController with endpoints:
    • GET /api/v1/settlements: List settlements with filtering.
    • GET /api/v1/settlements/:id: Get settlement details.
    • GET /api/v1/settlements/pending: Get pending settlements.
    • GET /api/v1/settlements/statistics: Get settlement statistics.
    • GET /api/v1/settlements/:id/receipt: Generate settlement receipt.
    • POST /api/v1/settlements/batch: Manual batch settlement.
    • GET /api/v1/settlements/schedule: Get settlement schedule.
    • PUT /api/v1/settlements/preferences: Update settlement preferences.
    • GET /api/v1/settlements/history: Get settlement history.
  • Updated SettlementService with business logic for all endpoints.
  • Added findByIds method to SettlementRepository for batch processing.
  • Implemented DTOs: SettlementGenericFilterDto, SettlementPreferencesDto, BatchSettlementDto, SettlementResponseDto.
• Tests:
  • Added test/settlement.e2e-spec.ts for integration testing.
• Dependencies:
  • Downgraded uuid to v9 to resolve Jest ESM compatibility issues.
• Configuration:
  • Updated .env with CHAIN_ID and JWT_SECRET for testing purposes.

Closes #34