Playbook actions: read (UIA text) + shell (external command)

YAML playbook actions 'read' and 'shell'. 'read' extracts text from a UIA/OCR target via UiaLocator.GetText and optionally stashes to a scenario variable. 'shell' runs an external command with timeout, captures stdout/stderr, honors expected exit_code, and can store stdout as a variable. Both resolve ${vars} in params.

Steps