Governed lifecycle hooks for persistent rooms

Expose a reviewed, room-scoped hook layer over Pi’s existing lifecycle events. Initial events: before_tool, after_tool, and before_finish. Hooks inherit room permissions, have bounded execution, produce audit receipts, and may observe, block, request approval, or return corrective feedback.

No files or tests are named. Start by locating Pi's existing lifecycle event integration, then trace room permissions and audit receipt handling; done means a reviewed room-scoped layer supports before_tool, after_tool, and before_finish with bounded execution and the stated observe, block, approval, and corrective-feedback outcomes.

Written by the indexing model from the issue text.