Why: The current main adds private project member event handling that must coexist with U3 task projections.
Evidence: Resolved cardsvc and SSE conflicts; corrected atomic project-event proof placement after a compile RED; go test ./... -count=1 passed.
Impact: Preserve both private project visibility and task checkpoint behavior; no real-model rerun.
Refs: Backend PR #193; Dev task feature/fast-slow-u2-u3-plan