Connecting to the bigger picture

This ApprovalPolicy slots into the exact spot Chapter 6 reserved in ToolRegistry.call, turning the agent's hands into gated hands. The mode field mirrors Claude Code's permission modes and feeds Chapter 12's budgets and hooks (a PreToolUse hook is another place to block commands). The guardian-subagent idea connects forward to Chapter 11's subagents and Chapter 13's security agents, which are guardians scaled up into full reviewers. In the capstone, no tool runs except through gated_call.