- Replaced `pendingCodexFunctionCall` with `codexFunctionCallStream` for enhanced function call tracking.
- Introduced `DeferredStreamEvents` to handle deferred event processing.
- Simplified and standardized codex function call state management with consolidated methods.
- Enhanced reasoning and thinking block handling to ensure proper closure and new block initiation.
- Removed redundant methods, improving maintainability.
Closes: #4655