guide

Protocol for the ctx-guard context and usage guard, and how to configure it. Use whenever a message starting with "[ctx-guard]" arrives (a context or usage note, a prompt turn saying the user is away, a refused ready token, a blocked tool, a lifted brake, a subagent budget note), when asked to write a ctx-guard handoff or end a reply with the ready token (CTX-READY), and when the user asks to set up, explain or change ctx-guard, a context guard or usage guard, its roles, thresholds, triggers, handoff, auto clear or compact, subagent budgets, trust or the /ctx-guard command.