Composes the ALLOW/ASK/DENY engine into the Raxol.Agent.CommandHook chain.

This is the integration seam: where Raxol.Agent.PermissionHook is deny-only, this hook evaluates the authorization engine at the :tool_call phase for each directive and maps the decision to a hook result:

• ALLOW -> {:ok, command} (commit labels)
• DENY -> {:deny, reason} (commit prior-ALLOW labels)
• ASK -> resolved synchronously via a :prompter (the same pattern PermissionHook uses); on approve {:ok, command} + release escrow, on deny {:deny, {:ask_denied, prompts}}. With no prompter, a pending ASK is denied {:deny, {:requires_approval, prompts}}.

Configure per process (like PermissionHook) with configure/1; the engine State (labels, approvals) is held in the process dictionary and threaded across calls. When not configured, the hook is a neutral no-op so it composes safely with other hooks.