FenrirCait/dsh-fail-guard

Stops the agent after N consecutive failures on the same tool. Instead of another retry it pushes a four-part stop instruction: what was tried, the exact error text, the likely cause, and what the user must do. Detection reads real tool results (isError or a non-zero shell exit code) and mirrors them through agent.steer, so the agent sees it as an inbound message rather than a log line.