- Updated all handlers to safely unlock the request mutex only if it's non-nil.
- Enhanced mutex locking and unlocking logic to avoid runtime errors.
- Improved robustness of resource cleanup across clients.
Add `GetRequestMutex` method for synchronization across clients
- Introduced a new `GetRequestMutex` method in OpenAICompatibilityClient, CodexClient, GeminiCLIClient, GeminiClient, and QwenClient for request synchronization.
- Ensures only one request is processed at a time to manage quotas effectively.