Split the three oversized test files into support modules and topic files, evaluate the rmdir dir_fd capability once at import, and drop unused imports. Claude-Session: https://claude.ai/code/session_01Agoc9bRVE9KL7mmWtey9Vq
Move the four providers onto _runtime and _shell_command; expected runtime scripts take the runtime config; add unique_preconditions. Claude-Session: https://claude.ai/code/session_01Agoc9bRVE9KL7mmWtey9Vq