DL-450

Board ref state is derived from stored pull_requests and issues rows, never a live forge read; KEY-N joins the Linear issues row kept by the Linear board ingest (no watch table); the PR gate adds merge-queue, conflict and stale-approval states (an approval is current only on head_sha)

Status: Active (Matt, 2026-10-10)

Record: ../../agent/compass-agent-status-record/design.md#d3-derived-state-comes-from-stored-rows-never-a-live-forge-read