Pending confirmation cards for ONE session, in the exact shape the SSE tool_confirmation_required event uses — so the frontend can re-render live cards when a session is OPENED (Recent panel / page refresh), where no POST happens and the SSE reconnect re-emit (agent.py, Task 12) never fires.

Live-caught 2026-07-13 (run 23, Bruce): a browser restart mid-review made the pending card unrecoverable — it existed only as a DB row until TTL expiry. History replay deliberately skips confirmation events (they'd render dead buttons); THIS endpoint is the live complement. Owner-scoped: only the caller's own pending rows, filtered to the requested session.