Why: collaboration storage U7 (proposal sections 3/5/7) requires two-process
HTTP-level acceptance over shared PG, a reproducible load-test entry honoring
the load contract, and an auditable pre-release checklist; capacity windows and
dual-host runs need user-scheduled resources, so the deliverable here is the
verifiable entry, not capacity claims.
Evidence: make test green (composite); make test-multi-instance green locally
against an isolated PG (five scenarios incl. crash-takeover and restart
invariants); run_load.sh --profile smoke end-to-end green (SSE probe p95~18ms,
zero seq duplicates, stack auto-recycled); backend pinned to feature branch
with the three cross-instance fixes.
Impact: new tests/integration/multi-instance (CI test-pg job step), new
tests/load/collaboration (k6 + SSE probe + run_load.sh), release checklist at
docs/release-multi-instance.md; no runtime behavior change in Dev repo itself.
Refs: backend PR #164; task card feature/u7-load-fault-release.
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