[FEATURE]: Migrate to native fetch from axios

[Fidelisaboke]

Feature Summary

Replace apiClient to use native fetch API over axios library

Motivation

Native fetch may just be good enough for the project. This will remove external dependencies.

Proposed Solution

• Refactor apiClient.ts to use fetch over axios client.
• Update all affected files to use native fetch for all API calls.

Alternatives Considered

No alternatives

Additional Notes

No response