- Enhanced the `Client` initialization to include `TokenStorage` and configuration parameters.
- Replaced `SaveTokenToFile` with a `Client` method for better encapsulation.
- Improved onboarding flow with project ID verification and API enablement checks.
- Refactored token saving logic to ensure proper handling of directory creation and JSON encoding.
- Removed unused file-related code in `auth.go` for improved maintainability.
- Moved login and service management logic to `internal/cmd` package (`login.go` and `run.go`).
- Introduced `DoLogin` and `StartService` functions for modularity.
- Enhanced error handling by using structured `ErrorMessage` in `Client`.
- Improved token file saving process and added project-specific token identification.
- Updated API handlers to handle more detailed error responses, including status codes.