Test: Add comprehensive unit tests for ClaimLookupProvider

[Cybermaxi7]

Test: Add comprehensive unit tests for ClaimLookupProvider (#ISSUE_NUMBER)

Description

This PR adds comprehensive unit test coverage for the ClaimLookupProvider, which is responsible for retrieving claim details by ID from the database.

Changes Made

• Created src/modules/claims/providers/claim-lookup.provider.spec.ts with 12 test cases
• Achieved 100% test coverage for ClaimLookupProvider (statements, functions, lines)
• Followed existing test patterns from claims.service.spec.ts

Test Coverage Includes

Test Case	Description
✅ Provider instantiation	Verifies the provider is properly defined and injectable
✅ Retrieve claim by ID	Verifies repository query with account relation
✅ Return ClaimDetailsDto	Verifies proper DTO formatting with all fields
✅ NotFoundException	Verifies error handling for non-existent claims
✅ Logger - lookup attempt	Verifies info log when starting lookup
✅ Logger - warning	Verifies warning log when claim not found
✅ Logger - success	Verifies success log when claim retrieved
✅ Database error propagation	Verifies connection errors are handled
✅ TypeORM query errors	Verifies query errors are propagated
✅ Edge case - USDC asset	Verifies different asset types work correctly
✅ Edge case - small amounts	Verifies very small amount handling
✅ Edge case - large amounts	Verifies large amount handling

Acceptance Criteria Met

• All tests pass (npm test -- claim-lookup.provider.spec.ts)
• 100% test coverage for ClaimLookupProvider
• Proper mocking of TypeORM repository
• Proper mocking of Logger
• All lint checks pass (npm run lint)
• Build succeeds (npm run build)
• Inline documentation comments included

Test Results

closes #40

Test Suites: 1 passed, 1 total
Tests:       12 passed, 12 total
Coverage:    100% Stmts | 100% Funcs | 100% Lines