Extract Common HTTP Client Logic

[mcncl]

Description

This PR introduces a new internal/http package that provides a common HTTP client for making API requests. The implementation standardizes the way we set up authorization headers, handle errors, and process responses across the codebase.

Motivation

Previously, HTTP request setup with authorization appeared in multiple places:

1. In pkg/cmd/api/api.go (apiCaller function)
2. In internal/config/token.go (fetchTokenInfo method)

Both set up similar HTTP clients, handle authorization, and process responses, but with slightly different approaches. This led to code duplication and potential inconsistencies in error handling. By extracting this common logic into a single package, we can reduce duplication and ensure consistent behavior across the codebase.

Changes

• Created new internal/http package with:
  • A client that handles common API operations (GET, POST, PUT, DELETE)
  • Standardized authorization header handling
  • Consistent error handling with detailed error messages
  • Support for configurable base URL and user agent
  • Comprehensive test suite
• Refactored pkg/cmd/api/api.go to use the new HTTP client
• Refactored internal/config/token.go to use the new HTTP client
• Added documentation for the new package

Testing

The changes are covered by new unit tests in the internal/http package.