Replace message handling with a chat session model, aligning the logic with new API requirements. Adjust functions to properly build chat history and send messages via chat sessions, improving compatibility and extensibility.
Implemented a nil check for Toolbox to prevent potential nil pointer dereferences. Cleaned up and reorganized code for better readability and maintainability while keeping placeholder functionality intact.
Anthropic API does not support assistants sending images directly, so the role is adjusted to "user" for such messages. This ensures compatibility and prevents errors when processing image messages.
Modify `FunctionCall` struct to handle arguments as strings. Add debugging logs to facilitate error tracing and improve JSON unmarshalling in various functions.
