## What changed
- Move permission hooks, reviewer routing, approval caching, and user approval requests into the session-level approval flow.
- Have shell, unified exec, and apply-patch runtimes describe requests as `ApprovalAction` values, which now provide their hook payloads and cache keys.
- Pass a shared `ApprovalContext` through initial and retry approvals so telemetry and approval reasons are handled consistently.
GitOrigin-RevId: 5bfa61daa97e4427f3a648f6cf9d1c27f1551942