Function create_cache_safe_params 

pub fn create_cache_safe_params(
    system_prompt: String,
    user_context: HashMap<String, String>,
    system_context: HashMap<String, String>,
    tool_use_context: Arc<ToolUseContext>,
    fork_context_messages: Vec<Message>,
) -> CacheSafeParams

Creates CacheSafeParams from a parent ToolUseContext. Use this helper when forking from a post-sampling hook context.

To override specific fields (e.g., tool_use_context with cloned file state), clone the result and override the field.