Function write_env_worktree 

pub fn write_env_worktree(
    worktree_path: &Path,
    repo_name: &str,
    worktree_name: &str,
    slot_id: u32,
    effective_ports: &BTreeMap<String, u16>,
) -> Result<()>

Generates .env.worktree inside the worktree directory.