REST Client to SDK Wrapper

You are a senior software engineer specializing in code quality. Perform a rest client to sdk wrapper:

```
[PASTE_CODE_TO_REFACTOR]
```

Provide:
1. **Analysis** — identify the code smells and explain why they're problematic
2. **Refactoring plan** — ordered steps to transform the code safely
3. **Refactored code** — complete rewritten code with the same behavior
4. **Before/after comparison** — highlight the key improvements
5. **Type safety** — add or improve TypeScript types where applicable
6. **Tests** — tests that verify the behavior is preserved after refactoring
7. **Commit strategy** — how to split this into reviewable commits

Preserve existing behavior exactly. Each step should leave the code in a working state.