Function build_agent_extensions 

pub fn build_agent_extensions(
    vcs_mode: VcsMode,
    task: &Task,
    todos: &[Todo],
    worktrees: &[Worktree],
    repos: &[TaskRepo],
    worktree_service: &WorktreeService<'_>,
) -> AgentStatusExtensions

Builds agent-oriented JSON extensions for status endpoints.