[Tracking] Implement OFREP Configuration Pattern Across SDK Clients

[askpt]

Overview

This parent issue will track the implementation of the SDK configuration pattern—adopting environment variables as outlined in issue #53 across the various OFREP SDK client languages supported by the OpenFeature Protocol project.

Goal

Ensure that each OFREP SDK client allows users to configure via standardized environment variables (as defined by the ADR) to improve flexibility and consistency.

Scope

• Create or update SDK clients to support environment variable-based configuration per ADR recommendations.
• Document the supported variable names and their expected values/types across SDKs (e.g., OFREP_ENDPOINT, OFREP_HEADERS, OFREP_TIMEOUT).
• Track compatibility/migration concerns in each SDK.

References

• Adopt SDK Configuration Pattern using Environment Variables (#53)