enhancement: add automated unit tests for SDK helper functions

[devmocrea]

Description

Set up a test environment inside packages/sdk using Vitest. Write unit tests to verify the correctness of all core utilities.

Technical Specification

• Install vitest in packages/sdk.
• Create a test file packages/sdk/src/__tests__/sdk.test.ts.
• Write tests verifying address structure exports and helper mapping utilities.

Acceptance Criteria

• Running pnpm test in the SDK directory runs all tests successfully.