Preserve approval baselines across forwarded wait chunks #21

A multi-chunk wait forwarded to another environment can miss an approval raised between chunks: each remote call rebuilds its initial approval baseline. The approval remains visible as pending, but the logical wait may not return until its timeout.

Original finding: #10 (comment)
Original reviewed SHA: 63b6c1b (Codex, P2).
Reverified at PR #10 head bb9fe41 on 2026-11-12: PeerForwarding.waitForThread reconstructs separate wait calls; ThreadManagementService.waitForThread snapshots pending approvals per call.
Root-cause key: peer-wait/approval-baseline-across-chunks.

Preserve one decision baseline across a logical forwarded wait without changing MCP approval authorization or causing immediate re-wait loops. Scope is the peer wait chunk path and its tests; no authentication or migration changes. Existing approval responses over MCP must remain refused.

Acceptance: a deterministic test raises an approval between one remote timeout response and the next request, and the logical wait returns waiting without consuming its full timeout. Existing pre-existing-approval and untilDelegatedWorkSettled behavior still passes. Use Deferred/event milestones, without sleeps or polling.

Disposition: nonblocking P2 follow-up for #10 (latency in a narrow round-trip gap). The earlier comment deferred it but did not create an issue. The batch author remains the follow-up owner; next action is a focused peer-protocol design/test when this issue is scheduled. Existing behavior remains the rollback. No fix is claimed by resolving the review conversation.