Refactor LlmController and AiChatService for SSE integration and Redis support

- Updated LlmController to implement a new SSE endpoint for streaming LLM progress updates, utilizing Redis pub/sub for real-time communication.
- Removed SignalR dependencies from AiChatService, replacing them with SSE logic for message streaming.
- Enhanced error handling and logging for Redis interactions, ensuring robust feedback during streaming operations.
- Adjusted request models and methods to accommodate the new streaming architecture, improving clarity and maintainability.

docs/TASK_ENVIRONMENTS_SETUP.md

@@ -178,3 +178,4 @@ Task Environment (offset ports)
 
 
 
+